Bent axis variable delivery inline drive axial piston pump and/or motor

ABSTRACT

A bent axis, variable displacement inline drive device may comprise: a port plate having fluid passages; a cylinder block rotatably mounted adjacent the port plate and having axial cylinders having openings in alternating fluid communication with the fluid passages; a rotatable shaft coupled through the port plate to the cylinder block, pistons in the cylinders and having a connecting rod extending from the cylinder block; a rotatable spindle having receptacles for receiving the connecting rods; a pivotable yoke having the spindle rotatably mounted thereon, whereby the rotating group comprising the spindle, pistons and cylinder block are connected by the connecting rods for rotating together, the yoke being pivotable for angling the spindle relative to the cylinder block. The device may be employed as a pump, or as a motor, or as both a pump and a motor, and the yoke may be pivoted over center.

This application claims the benefit of U.S. Provisional Patent Application No. 61/594,091 entitled “BENT AXIS VARIABLE DELIVERY INLINE DRIVE AXIAL PISTON PUMP AND/OR MOTOR” filed on Feb. 2, 2012, which is hereby incorporated herein by reference in its entirety.

The present invention relates to an axial piston device and, in particular, to an axial piston pump and/or motor device including inline drive and a bent axis.

Known fluid axial piston pumps, e.g., as may be employed as hydraulic pumps, fall into two fundamentally and distinctly different categories: a bent axis axial piston pump or an inline drive axial piston pump.

A rotating type of axial piston pump has a rotatable cylinder block or cylinder barrel having a plurality of parallel cylinders arranged in an axial circular array therein which is rotatable about its central axis. Each cylinder has a reciprocating piston therein that is driven (as explained below) to move in an axial direction through one complete reciprocation cycle within the cylinder with each 360° rotation of the cylinder block. One flat end face of the cylinder block abuts a flat valving surface of a valve plate that has a curved inlet passage coupled to an inlet port and a curved outlet passage coupled to an outlet port. The cylinder block is rotated relative to the valve plate to operate the pistons and to cause the pumping action of the cylinders to pump fluid from the inlet port to the outlet port. The cylinder block is driven by a shaft and disk that is located at the end of the cylinder block remote from the end that abuts the valve plate, wherein the disk is mechanically connected to the pistons to cause reciprocating movement thereof as the cylinder block rotates.

Each of the curved passages in the valve plate has an opening or slot in the shape of a partial circular arc of less than 180° at the flat valving surface of the valve plate so as to be in fluid communication with the open ends of the cylinders at the flat end face of the cylinder block for less than 180° of rotation of the cylinder block. Each cylinder is thus in fluid communication with the inlet passage during less than 180° of rotation of the cylinder block and is in fluid communication with the outlet passage during less than 180° of rotation of the cylinder block, as it moves along a circle abutting the valving surface of the valve plate.

Each piston is actuated reciprocally so as to be moving away from the valve plate when its cylinder is open to the inlet passage, thereby to draw fluid into the cylinder, and to be moving toward the valve plate when its cylinder is open to the outlet passage, thereby to expel fluid out of the cylinder. Thus, fluid in the inlet passage is drawn into the cylinders from the inlet passage and is expelled from the cylinders into the outlet passage, thereby producing the desired flow by the pumping of fluid from the inlet port to the outlet port. The volume of fluid pumped is substantially proportional to the displacement of the cylinders and the rate of rotation of the cylinder block.

FIG. 1 includes FIGS. 1A and 1B which are cross-sectional views taken 90° rotationally apart of an example embodiment of a conventional bent axis axial piston pump 900. Therein, a rotatable drive shaft 910 rotates in a housing 920 about an axis 912 that is offset at an angle relative to the rotation axis 932 of the cylinder block 930 and has a drive disk 940 that is affixed perpendicular to the rotational axis 912 of the drive shaft 910 and rotates therewith. The drive disk 940 has a circular array of sockets 942 in which are retained connecting rods 952 of the pistons 950 in the cylinder block 930 so that the drive shaft 910, drive disk 940 and cylinder block 930 all rotate together. Because the drive shaft 910 is at an angle α relative to the cylinder block 930, the piston rods 952 and pistons 950 are driven in reciprocating manner by rotation of the drive shaft 910, drive disk 940 and cylinder block 930 therewith, and the distance each piston 950 moves is related to the angle α. Typically, a universal joint or link may be provided between the end of the drive shaft 910 and the cylinder block 930, e.g., at or near the intersection of their respective axes 912, 932 of rotation, to rotationally drive the cylinder block 930.

Fluid moves through pump 900 via fluid passages in yoke 960 and a port plate 970 thereon adjacent to the rotating cylinder block 930. The bearings pivotably supporting yoke 960 typically include seals 924 allowing relative pivoting rotation between the fluid passages of yoke 960 and those of fluid ports 922 of housing 920. The pivotable parts of pump 900 including cylinder block 930, yoke 960 and port plate 970 are relatively larger and heavier parts of pump 900 and so tend to be difficult to move (pivot) quickly or easily. Drive shaft 910 is typically supported by one or more bearings 914 and seals 916 for enabling the rotation thereof.

Where the angle α between the drive disk 940 and the cylinder block 930 is fixed, so is the movement and displacement of the pistons 950, and the pumping volume. However, if the drive shaft 910 and drive disk 940 are mounted on a movable pivoted yoke 960 so that the angle α between the drive shaft 910 and the cylinder block 930 can be changed, then by varying the angle α the magnitude of the reciprocating movement of the pistons 950 may be changed and a variable displacement pump 900 may be obtained. When the drive shaft 910 and cylinder block 930 are aligned, e.g., angle α is zero, the pistons 950 do not reciprocate and so no fluid is pumped. Because the displacement varies as the sine of angle α, a larger angle α produces a greater displacement of pistons 950 and a greater pumped volume at a given cylinder block 930 rotation rate.

While the bent axis axial piston pump 900 is very efficient and was the dominant type of hydraulic pump employed, e.g., in aircraft for many years, one disadvantage of the bent axis axial piston pump 900 is that the rotating group including the entire assembly of drive shaft 910 and drive disk 940 must be moved by the pivoted yoke 960 to effect variable displacement. As a result, bent axis axial piston pumps 900 tend to be large and heavy, and to be difficult to make as a variable delivery pump. The angle α represents the maximum angle α that can practically be utilized in a fixed displacement bent axis pump, e.g., about 40° and the maximum change in angle α in a variable displacement bent axis pump is about 28°-30°. Moreover the rotating fluid seals 924 between the fluid passages of yoke 960 and housing 920 may become a source of leaks of the fluid which may be pumped under relatively high pressure. For these reasons, despite its inherent high pumping efficiency, the conventional variable displacement bent axis axial pump has been superceded, at least in aircraft and aerospace applications, by the smaller and lighter conventional inline drive axial configuration pump, albeit at lower pumping and mechanical efficiencies.

FIG. 2 is a cutaway perspective view of an example embodiment of a conventional inline drive axial piston pump 800 which was introduced about in the mid-1960's. Therein, a rotatable drive shaft 810 rotates about an axis 812 that is coaxial with the rotation axis 81 of the cylinder block 830 and rotates therewith, and includes a non-rotating swash plate 840 that is angled relative to the axis of the drive shaft 810. The swash plate 840 has a rotatable drive disk 844 thereon having a circular array of sockets 842 in which are retained the connecting rods (also known as shoes or slippers) 852 of the pistons 850 which move reciprocally in bores in the cylinder block 830 so that the drive shaft 810, drive disk 844 and cylinder block 830 all rotate together. Because the drive disk 844 and swash plate 840 swivel together and are at an angle relative to the cylinder block 830, the pistons 850 are driven in reciprocating manner by rotation of the drive shaft 810 and the cylinder block 830 therewith, and the distance each piston 850 moves is related to the angle that swash plate 840 is offset from being perpendicular to the axis 812 of drive shaft 810. The drive shaft 810 and the cylinder block 830 are coaxial and so may be directly coupled mechanically. However, the sliding action of piston shoes/slippers 852 in the receptacles of swash plate 840 tends to produce stick-slip friction that precludes operation at low speeds and reduces efficiency.

Where the angle between the drive disk 844 and the cylinder block 830 is fixed, so is the displacement of the pistons 850, and the pumping volume. However, if the drive disk 844 is mounted on a movable pivoted swash plate 840 so that the angle between the drive disk 844 and the cylinder block 830 can be changed, then by varying that angle the magnitude of the reciprocating movement of the pistons 850 may be changed and a variable displacement pump 800 may be obtained pumping fluid between inlet and outlet ports 822. When the swash plate 840 and drive disk 844 are perpendicular to the drive shaft 810, e.g., angle is zero, the pistons 850 do not reciprocate and so no fluid is pumped. Because the displacement varies as the sine of the angle between the drive disk 844 and the cylinder block 830, a larger angle produces a greater displacement and a greater pumped volume at a given cylinder block 830 rotation rate.

While the inline axial piston pump 800 can be compact in size relative to a comparable bent-axis piston pump, disadvantages of the inline axial piston pump 800 include lower pumping and mechanical efficiency than the bent axis piston pump, that the inline drive piston pump can be run in only one direction, cannot be operated over center, cannot be operated as both a pump and a motor, and cannot be operated at low speed. The maximum angle that the drive disk can be swiveled from perpendicular has for many years been limited to about 18° from perpendicular which limits the maximum displacement this type of pump can provide; even with recent advances that allow that angle to be increased to about 21°, the displacement is still limited. The conventional inline axial structure cannot be run over center and so cannot be reversed.

Thus, existing axial piston pumps all suffer from a limitation in capacity due to the practical limitation of the maximum angle permissible between the cylinder block and the drive disk and/or swash plate. It would be desirable to have an axial piston device, e.g., a pump and/or motor, that is operable with a greater angle, which would yield a reduction in weight and size to produce a given flow. Further, it would also be desirable to provide an axial piston device or machine that could provide inherently lower losses leading to higher pumping and mechanical efficiencies. In addition, it would be desirable to have an axial piston device or machine that is not limited by having the drive shaft at the opposite end from the inlet and outlet ports and/or that has a pivoted structure that is of reduced size and/or mass to obtain variable displacement, and therefore provides faster response, e.g., in changing displacement.

Applicant believes there is a need for an axial piston pump and/or motor that is not subject to one or more of the foregoing limitations.

Accordingly, a bent axis, variable displacement inline drive device may comprise: a port plate having fluid passages therein; a cylinder block rotatably mounted adjacent the port plate and having an array of axial cylinders having openings adjacent the port plate located to be in alternating fluid communication with the fluid passages; a rotatable shaft coupled through an opening in the port plate to the cylinder block for rotating therewith; a plurality of pistons disposed in the cylinders of the cylinder block for reciprocating motion therein, each piston having a connecting rod extending from an end of the cylinder block; a rotatable spindle having receptacles for receiving the connecting rods; a pivotable yoke having the spindle rotatably mounted thereon, whereby the spindle and plurality of pistons disposed in the cylinder block are connected by the connecting rods for rotating together, the yoke being pivotable for angling the spindle relative to the cylinder block. The device may be employed as a pump, or as a motor, or as both a pump and a motor, and the yoke may be pivoted over center.

According to another aspect, a bent axis, variable displacement inline drive pump device may comprise: a port plate having fluid passages therein; a cylinder block rotatably mounted adjacent the port plate and having an array of axial cylinders each having an opening adjacent the port plate to be in alternating fluid communication with the fluid passages; a rotatable shaft coupled through an opening in the port plate to the cylinder block for rotating therewith; a plurality of pistons disposed in the cylinders of the cylinder block for reciprocating motion therein, each piston having a connecting rod extending therefrom; a rotatable spindle having receptacles for receiving the connecting rods; a pivotable yoke having the spindle rotatably mounted thereon, whereby the spindle and plurality of pistons disposed in the cylinder block are connected by the connecting rods for rotating together, the yoke being pivotable for angling the spindle relative to the cylinder block. The yoke may be pivoted over center.

According to another aspect, a bent axis, variable displacement inline drive motor device may comprise: a port plate having fluid passages therein; a cylinder block rotatably mounted adjacent the port plate and having an array of axial cylinders therein each having an opening adjacent the port plate to be in alternating fluid communication with the fluid passages; a rotatable shaft coupled through an opening in the port plate to the cylinder block for rotating therewith; a plurality of pistons disposed in the cylinders of the cylinder block for reciprocating motion therein, each piston having a connecting rod extending therefrom; a rotatable spindle having receptacles for receiving the connecting rods; a pivotable yoke having the spindle rotatably mounted thereon, whereby the spindle and plurality of pistons disposed in the cylinder block are connected for rotating together, the yoke being pivotable for angling the spindle relative to the cylinder block. The yoke may be pivoted over center.

In another aspect, a bent axis, variable displacement inline drive device rotating group may comprise: a cylinder block rotatably mountable and having an array of axial cylinders each having an opening located to be in alternating fluid communication with fluid passage openings of a port plate; the cylinder block having a central opening for receiving a rotatable shaft, whereby a rotatable shaft may be coupled to the cylinder block through an opening in a port plate; a plurality of pistons disposed in the cylinders of the cylinder block for reciprocating motion therein, each piston having a connecting rod extending from an end of the cylinder block; a rotatable spindle having a circular array of receptacles for receiving the ends of the connecting rods; a pivotable yoke having the spindle rotatably mounted thereon for rotation, whereby the spindle and plurality of pistons are connected by the connecting rods for rotating together, the yoke being pivotable for angling the spindle relative to the cylinder block. The device rotating group may be employed as a pump, or as a motor, or as both a pump and a motor, and the yoke may be pivoted over center.

BRIEF DESCRIPTION OF THE DRAWING

The detailed description of the preferred embodiment(s) will be more easily and better understood when read in conjunction with the FIGURES of the Drawing which include:

FIG. 1 includes FIGS. 1A and 1B which are cross-sectional views taken 90° rotationally apart of an example embodiment of a conventional bent axis axial piston pump;

FIG. 2 is a partially cutaway perspective view of an example embodiment of a conventional inline drive axial piston pump;

FIG. 3 is a perspective view of an example embodiment of a bent axis variable delivery inline drive axial piston pump and motor according to the present arrangement, with the housing thereof illustrated as transparent to reveal interior parts;

FIG. 3A is a perspective view showing rotating components of the example bent axis variable delivery inline drive axial piston pump and motor, and FIG. 3B is a perspective view of an example port plate therefor;

FIG. 4 is a side view of the example bent axis variable delivery inline drive axial piston pump and motor, with the housing thereof illustrated as transparent to reveal interior parts;

FIG. 5 is a side cross-sectional view of the example bent axis variable delivery inline drive axial piston pump and motor;

FIG. 5A is an enlarged side cross-sectional view of the example bent axis variable delivery inline drive axial piston pump and motor showing certain details of the yoke assembly thereof;

FIG. 6 includes FIGS. 6A-6G which are a series of partially transparent perspective views showing rotating and movable components of the example bent axis variable delivery inline drive axial piston device employed as a pump with the yoke thereof moved to different angular positions;

FIG. 7 includes FIGS. 7A-7G which are a series of partially transparent perspective views showing rotating and movable components of the example bent axis variable delivery inline drive axial piston device employed as a motor with the yoke thereof moved to different angular positions;

FIG. 8 includes FIGS. 8A and 8B which are schematic diagrams representing a parallel and a series configured, respectively, kinetic energy recovery systems and/or hydraulic hybrid drive systems, and

FIG. 9 includes FIGS. 9A-9H which are a series of partially transparent perspective views showing rotating and movable components of the example bent axis variable delivery inline drive axial piston device employed as a pump and motor in a kinetic energy recovery system and/or in a hydraulic hybrid drive system, with the yoke thereof moved to different angular positions in different ones of FIGS. 9A-9H.

In the Drawing, where an element or feature is shown in more than one drawing figure, the same alphanumeric designation may be used to designate such element or feature in each figure, and where a closely related or modified element is shown in a figure, the same alphanumerical designation may be primed to designate the modified element or feature. According to common practice, the various features of the drawing are not to scale, and the dimensions of the various features may be arbitrarily expanded or reduced for clarity, and any value stated in any Figure is by way of example only.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

A bent axis variable delivery inline drive axial piston pump and/or motor 100 according to the present arrangement differs substantially from both a conventional bent-axis axial piston pump and from a conventional inline drive axial piston pump. In the present arrangement, pump and/or motor device 100 has its drive connection at the port plate 120 end thereof, and not at the drive plate or swash plate end as in conventional bent-axis axial piston pumps and conventional inline drive axial piston pumps. Thus, when device 100 is employed as a pump 100, the driving device, e.g., an electric or other motor 175, is connected at the port plate 120 end and is fixedly mounted, and when device 100 is employed as a motor 100, the output drive shaft 170 is at the port plate 120 end and may be fixedly connected to a driven load. If device 100 is employed as both a pump and a motor, both the input drive and the output to a load are connected at shaft 170. Because the yoke 160 of device 100 can be operated “over center,” i.e. at both positive and negative angles relative to the rotational axis of cylinder block 130, the device 100 can be run in both directions and can be operated both as a motor and as a pump. Also, because the internal friction is rolling friction and not stick-slip friction, device 100 can be operated at low speed and with high mechanical efficiency.

In addition, the rotating cylinder block 130 is inline with the drive shaft, whilst the yoke 160 and spindle 150 are in a bent axis configuration and are the only parts that must be pivoted for providing variable delivery (variable displacement), thereby enabling a reduced size (volume) while retaining certain efficiency advantages of a bent axis arrangement because the drive shaft and drive motor or load connection are at the port plate 120 end and need not be pivoted. Moreover, the pivotable yoke 160 and spindle 150 of the present device 100 have lower inertia and so can be pivoted more easily and more quickly, beneficially improving the response of device 100 to allow for faster changes in delivery volume.

Because device 100 is operable over yoke angles of at least about ±30° it can provide greater displacement, e.g., greater fluid flow, than a conventional bent axis pump or a conventional inline drive pump of comparable size. A conventional inline drive axial pump is not able to provide over center operation of a yoke as does device 100.

Thus, a device 100 may be employed as a pump or as a motor, or as both a pump and a motor, and in either or both uses can utilize over-center operation of yoke 160 to provide a reversible variable delivery (variable displacement) pump 100 and/or a reversible variable delivery (variable displacement) motor 100. In other words, when device 100 is employed as a pump, the direction of fluid flow produced by pump 100 can be reversed by pivoting yoke 160 without changing the direction of rotation of its drive shaft 170, and when device 100 is employed as a motor, the direction of rotation of drive shaft 170 can be reversed by pivoting yoke 160 without changing the direction of the flow of driving fluid through port plate 120.

Still further, the unique piston rod 140, spindle 150 and yoke 160 arrangement of device 100 can provide a pump and/or motor 100 of smaller size and weight, which is an advantage usually associated with an inline drive axial piston pump, and also with higher volumetric and torque efficiency, which is an advantage usually associated with a bent axis axial piston pump.

FIG. 3 is a perspective view of an example embodiment of a bent axis variable delivery inline drive axial piston pump and/or motor 100 according to the present arrangement, with the housing 180, 190 thereof illustrated as transparent to reveal interior parts thereof; FIG. 3A is a perspective view showing rotating components of the example bent axis variable delivery inline drive axial piston pump and/or motor 100, and FIG. 3B is a perspective view of an example port plate 110 therefor. Device 100 comprises a non-rotating port plate 110 having fluid passages 117 a, 117 b in fluid communication via openings 112 a, 112 b, respectively, with two fluid ports 120, typically located about 180° apart radially, through which fluid enters and leaves device 100. Port plate 110 has two fluid passages 117 a, 117 b, each having a port opening 112 a, 112 b that is coupled to one of the two ports 120 and having an arcuate chamber 117 a, 117 b with an arcuate slot or opening in cylinder seat surface 116 to which ports 133 of cylinders 132 of rotating cylinder block 130 come into fluid communication for less than 180° of each 360° rotation of cylinder block 130. Port plate 110 is disposed in a cavity in housing 180, e.g., in the central portion 184 thereof, wherein its fluid passages are in fluid communication with ports 120. Port plate 110 has a central opening 115 through which shaft 170 passes and is free to rotate.

Cylinder block 130 rotates relative to port plate 110 about an axis 102 that is perpendicular to port plate 110 and is coaxial with the rotational drive axis 102 of drive shaft 170. Shaft 170 extends through housing 180 and seals 172 and bearings 174 therein, through opening 115 of port plate 110 into cylinder block 130. Typically, cylinder block 130 has a central opening into which the end of shaft 170 extends and engages cylinder block 130, e.g., by the engaging of respective splines 171, one or more keys and slots, or other physical features 171 thereof. Thus, cylinder block 130 engages shaft 170 and rotates therewith. Preferably, shaft 170 and cylinder block 130 are closely connected and rotate as a unit that is supported radially at two places, e.g., by a spaced apart pair of bearings 136, 174.

Cylinder block 130 has a plurality of axial cylinders 132 therein, each cylinder 132 preferably having a cylinder port 133 at one end thereof that comes into fluid communication with each of the two fluid passages of port plate 110 alternatingly as cylinder block 130 rotates. Preferably, cylinder block 130 has an odd number of cylinders 142, typically either 7, 9 or 11 cylinders, and preferably 9 cylinders. In each cylinder 132 of cylinder block 130 is a piston 142 that is movable axially therein and that has a connecting rod 140 connected at one end thereof. As each piston 142 moves away from port plate 110 fluid flows from one fluid passage of port plate 110 into the cylinder 132 containing that piston 142, and as each piston 142 moves toward port plate 110 fluid flows from the cylinder 132 into the other fluid passage of port plate 110, so that for each rotation of cylinder block 130, each piston 142 makes one reciprocating cycle during which fluid moves from one fluid passage of port plate 110 into the other fluid passage, and thereby between one port 120 and the other port 120. If device 100 is being employed as a pump 100, then the pistons 142 which are driven synchronously with the rotation of cylinder block 130 reciprocate to move (pump) the fluid. If, however, device 100 is being employed as a motor 100, then the fluid is moved under pressure through ports 120 and port plate 110 to drive the pistons 142 in reciprocating movement thereby to impart rotary motion to cylinder block 130.

Device 100 has a housing typically provided by two or more housing parts, e.g., a shaft housing 180 and a yoke housing 190 that may be mated and attached at their respective mounting plates or flanges, e.g., by a plurality of fasteners. Port plate 110 and at least part of cylinder block 130 typically reside in shaft housing 180 through which passes a drive shaft 170 that provides a mechanical connection between cylinder block 130 and either a drive source, e.g., a motor 175, when device 100 is utilized as a pump, or a load when device 100 is utilized as a fluid driven motor. Thus, cylinder block 130 and drive shaft 170 are in an inline drive-like configuration, however, in this configuration drive shaft 170 passes through a drive opening 115 in port plate 110 and does not connect to or support a drive plate or a swash plate.

A pivotable yoke 160 and a rotatable spindle 150 that is rotatable on yoke 160 typically reside in yoke housing 190. Yoke spindle 150 rotates with cylinder block 130 and pivots (or swivels) with yoke 160. Yoke 160 typically includes a generally circular yoke plate 160P on which spindle 150 is rotatably mounted and a pair of yoke arms 164 extending from the yoke plate 160P, thereby to define a yoke 160. Each yoke arm 164 is connected to, e.g., an inner race member of yoke bearing 162 the outer race member of which is supported by yoke housing 190. Typically, each yoke arm or bearing plate 164 has, e.g., a circular opening in which is disposed the inner race member of yoke bearing 162 and yoke housing 190 has a corresponding recess in which is disposed the outer race member of yoke bearing 162.

Yoke 160 is thus pivotable on coaxial yoke bearings 162 the axes of which define a yoke pivot axis 163 that is perpendicular to and intersects the axis 102 of rotation of cylinder block 130 and drive shaft 170. As yoke 160 and rotatable spindle 150 thereon are pivoted, the rotational axis 161 of spindle 150 defines a plane that also contains the rotational axis 102 of cylinder block 130 and drive shaft 170 and to which the yoke pivot axis 163 is perpendicular. As a result, rotatable spindle 150 is in a variable angle relationship of defining an angle A with the axis 102 of cylinder block 130, e.g., in a bent axis-like configuration. Pivoting of yoke 160 causes the corresponding pivoting of spindle 150 rotatable thereon, with the result of changing the angle A between the rotation axis 161 of spindle 150 and the rotation axis 102 of cylinder block 130, thereby to change the distance that connecting rods 140 and pistons 142 travel in reciprocating motion and correspondingly change the displacement of pump and/or motor 100.

The components of device 100 comprising at least cylinder block 130, connecting rods 140, pistons 142 and spindle 150 may be referred to as a “rotating group” because all rotate together as a unit in operation in device 100, however, yoke 160 could in some cases also be considered as part of the rotating group, e.g., because spindle 150 could be provided rotatably mounted thereon in a typical replacement part. A rotating group of assembled components 130, 140, 150 and/or 160 might be made available as a replacement part so as to be easily replaceable as a unit or group, whether such part were to be available to the trade, or to an authorized repair and servicing agent or facility, or to both.

FIG. 4 is a side view of the example bent axis variable delivery inline drive axial piston pump and/or motor 100, with the housing 180, 190 thereof illustrated as transparent. Therein are seen additional details to the foregoing description of pump and/or motor 100. Shaft housing 180 is seen to have a shaft housing base 182 which may be employed for mounting pump and/or motor 100, a central portion 184 having a bore 185 for shaft 170 and related elements, and a port plate receiver portion 186 for receiving port plate 110 and ports 120 therein, and to which yoke housing 190 is attached. Ports 120 may be press fit, threadingly engaged or otherwise disposed in port plate housing portion 186 so as to couple to port openings 112 of port plate 110 and be sealed thereto.

Bore 185 in the central portion 184 of shaft housing 180 has an outer larger diameter portion in which are disposed a shaft seal 172 and a shaft bearing 174 for supporting and sealing around drive shaft 170 therein, and an inner smaller diameter portion in which shaft 170 passes through to then pass thorough drive opening 115 of port plate 110 to engage cylinder block 130 so that cylinder block 130 and drive shaft 170 rotate together.

Yoke housing 190 has a base portion that corresponds to the distal end of receiver portion 186 of shaft housing 180 so as to mate therewith, e.g., as by screws, bolts, or other fasteners in the corresponding holes thereof. Yoke housing 180 has a housing cover portion 194 extending from its housing base 192 to define a cavity in which is disposed pivotable yoke 160, wherein the cavity thereof is of sufficient size to permit full pivoting of yoke 160, e.g., to at least an angle A of about ±30° of pivoting relative to the rotational axis 102 of cylinder block 130 for varying the displacement of pump and/or motor 100 in proportion to the pivot angle.

Yoke housing cover 194 may have an opening 195 therein through which a mechanical connection from outside of pump and/or motor 100 may be made to one arm of yoke 160 for causing the moving of yoke 160 to desired pivot angles A relative to the rotational axis 102 of cylinder block 130. Mechanical connections thereto may include, e.g., mechanical linkages, rotatable shafts, flexible shafts, lever handles, hydraulic linkages and apparatus, electrical motors, stepper motors, solenoids, electronic controls, and the like, as may be suitable and convenient in any particular utilization of pump and/or motor 100.

While yoke 160 and spindle 150 thereon are illustrated as being pivoted to an example angular position, they may be pivoted to any angular position up to an angle A of at least about ±30° of pivoting relative to the rotational axis 102 of cylinder block 130 for obtaining a particular desired displacement of pump and/or motor 100. When the angle A is zero, e.g., axes 102 and 163 are substantially aligned, and piston rods 140 and pistons 142 do not move as cylinder block 130 and spindle 150 rotate, and so there is zero displacement of device 100, and no fluid is pumped when device 100 is employed as a pump 100 and no motion when device 100 is employed as a motor 100.

When the yoke 160 is pivoted in a first direction to increase angle A relative to drive axis 102, e.g., angle A becomes a positive value, then there is a certain defined relationship between the direction of flow of fluid between ports 120 and the direction of rotation of cylinder block 130 and spindle 150. However, when the yoke is pivoted in an opposite direction to the first direction to increase angle A, e.g., angle A becomes a negative value, then there is an opposite relationship between the direction of flow of fluid between ports 120 and the direction of rotation of cylinder block 130 and spindle 150. Thus, device 100 is reversible, whether employed as a motor 100 or as a pump 100.

FIG. 5 is a side cross-sectional view of the example bent axis variable delivery inline drive axial piston pump and motor 100, and FIG. 5A is an enlarged side cross-sectional view thereof showing certain details of the yoke assembly 160 thereof. Therein may be seen that drive shaft 170 is disposed through shaft housing 180 and port plate 110 to engage cylinder block 130 which rotates about axis 102 therewith, e.g., via the engaging of axial splines. Cylinder block 130 is supported by and rotates on a cylinder block bearing 136 that is retained in position by a bearing spring plate 138.

Between bearing spring plate 138 and bearing 136 is a spring 137, e.g., a wave spring or a Belleville spring, that urges cylinder block 130 towards and against port plate 120, thereby to minimize the leakage of fluid and allow fluid pressure to build when device 100 is not under fluid pressure. When device 100 is in operation, fluid pressure in cylinders 132 and cylinder ports 133 (which have a smaller diameter than do cylinders 132) provide force tending to urge cylinder block 130 towards and against port plate 120.

Shaft seal 172 in the larger diameter portion of bore 185 may include a seal carrier 172C having one or more cylindrical grooves 172G that carry respective sealing gaskets or other sealing material that is in sliding and sealing contact with the rotatable drive shaft 170. Shaft bearing 174 may be seen to be, e.g., a ball or roller type bearing wherein an inner race member is adjacent shaft 170 and on outer race member is adjacent shaft housing 180, whereby shaft 170 rotates about drive axis 102.

Cylinder block 130 may be seen to have a plurality of axial cylinders 132 therethrough of which one is visible. Cylinder 132 has a cylinder port 133 at the end thereof adjacent to port plate 110 that typically is of smaller diameter than is cylinder 132. One of the pistons 142 is seen in one of the cylinders 132 as having a generally spherical socket at the end thereof distal from port plate 110. Connecting rod 140 is seen to have generally spherical ends 144,146, one of which 144 is retained in a generally spherical socket 143 of piston 142, e.g., as by being swaged or otherwise retained therein, and the other end 146 of which is retained in a generally spherical socket 153 of rotatable spindle 150, e.g., by a hold down plate 152 that is attached to yoke spindle 150 and rotates therewith.

Because each end of each connecting rod 140 has a generally spherical ball and socket arrangement, each connecting rod 140 may position itself in a low stress position relative to a respective piston 142 and yoke spindle 150, thereby to move synchronously in rotation with cylinder block 130 and spindle 150 and in part to transmit forces to maintain such synchronous rotational movement, while causing reciprocating movement of pistons 142 in cylinders 132 that is synchronized with the rotation of cylinder block 130 and spindle 150. Connecting rods 140 may have a central axial passage, e.g., for allowing fluid to pass therethrough, e.g., to provide lubrication to spindle 150 and connecting rod ends 146 therein.

Because the pump/motor device 100 includes a bent axis like geometry, the total effective displacement of the pistons 142 and cylinder block 130 is a function of the circle diameter of the pistons 142 in the spindle 150 sockets 153, rather than the circle diameter of the pistons 142 in the cylinders 132 of cylinder block 130. Because the pistons 142 are splayed in the bent axis geometry, the yoke spindle socket 153 circle diameter of the yoke 160 spindle 150, by geometric necessity, is larger than the piston circle diameter in the cylinder block 130. Due to this splaying of the piston circle versus the yoke spindle socket circle, the present inline drive bent axis pump/motor device 100 has an advantage of greater spindle socket circle diameter than piston circle diameter. As a result, the flow advantage of having an increased maximum yoke angle A is beneficially increased further by the splayed spindle socket 153 circle diameter of the present bent axis geometry.

A universal link 200 connects the end of drive shaft 170 and spindle 150 on yoke 160. Universal link 200 is believed to not transmit a substantial torque between cylinder block 130 and spindle 150, but acts to ensure the synchronous rotational motion thereof.

In particular, when device 100 is utilized as a pump 100, cylinder block 130 is driven rotationally by drive shaft 170 and the connecting rods 140 transmit forces that tend to make spindle 150 follow cylinder block 130, thereby to cause the synchronous rotational motion thereof. When device 100 is utilized as a motor 100, the pressure of fluids passing between ports 120 via the cylinders 132 of rotating cylinder block 130 impart forces to pistons 142 that cause reciprocating motion thereof, and the connecting rods 140 transmit the forces from pistons 142 to spindle 150 to cause rotational motion thereof and the synchronous rotational motion of cylinder block 130.

Spindle 150 has a plurality of generally spherical sockets 153 therein that receive the generally spherical ends 146 of connecting rods 140 which are retained therein by a piston rod hold down plate 152 that is attached to and rotates with spindle 150. Spindle 150 rotates on the end plate 160 of yoke 160 and is supported axially by an axial bearing 154 and radially by a radial bearing 156 set in a spherical race 157. Bearing 156 is preferably a radial needle bearing housed in a spherical race 157 flanked by a cylindrical thrust roller bearing 154, the combination of which tends to provide a bearing arrangement that is tolerant of mis-alignment, e.g., of spindle 150 and/or yoke 160. The low inertia yoke 160 and low operating force required to pivot yoke 160 complements the alignment tolerant feature thereof.

Universal link 200 includes a linking rod 202 having a split generally spherical ball 204, 206, at each end thereof, one that resides in generally spherical socket 131 in cylinder block 130 and one in a generally spherical socket 151 in spindle 150, respectively. Each end of link 200 is keyed to its spherical socket 131, 151 so that link 200 constrains cylinder block 130 and spindle 160 to rotate together. Preferably a spring 169 is provided to bias the movable spherical socket 151 of spindle 150 towards and against rod end 206 of link 200 and towards cylinder block 130. Spring 169 permits the movable socket 151 to move as the effective geometric length of universal link 200 varies with the pivot angle A of yoke 160, e.g., to allow link 200 to “walk” as yoke 160 is pivoted Because spindle 150 and link 200 do not rotate about the same axis, the geometric length of link 200 is longest when yoke 160 is centered, e.g., at a yoke angle A of 0° and lessens as the magnitude of angle A increases as yoke 160 is pivoted off center, being shortest at the maximum value of angle A, e.g., at about ±30°. In one typical example, the difference in geometric length can be about ⅛ inch (about 3 mm).

One spherical end 204 of universal link 200 is centered on drive axis 102 on the drive shaft 170, cylinder block 130 side of yoke pivot axis 163 and the other end 206 of universal link 200 is centered on the spindle 150, yoke 160 side of yoke pivot axis 163. The halves of the split spherical balls 204, 206 may be brought closer together, e.g., by a threaded connection, so as to reduce their diameter for placing them in the respective sockets 131, 151, and then may be expanded, e.g., by the threaded connection, to correspond to an outer generally spherical shape so as to more fully fill sockets 131, 151 and be retained therein.

FIG. 6 includes FIGS. 6A-6G which are a series of partially transparent perspective views showing rotating components of the example bent axis variable delivery inline drive axial piston device 100 employed as a pump 100 with the yoke 160 thereof moved to different angular positions A. In FIGS. 6A-6G the arrows drawn in thin line represent the pump drive motion applied to device 100 employed as a pump 100, e.g., from an electric or other motive source, and the arrows drawn in outline represent the direction and volume of the flow of fluid produced by the pump 100. In general, the relation between fluid flow and rotational motion of drive shaft 170 is proportional to the displacement of cylinder block 130, the rate of rotation thereof and the sine of the angle A between the drive axis 102 and the yoke or spindle axis 161 of device 100. Mathematically:

FF=D×R×(sin A)×K,

wherein:

-   -   FF is fluid flow,     -   D is the displacement of all of pistons 142 in cylinder block         130,     -   R is the rate of rotation of shaft 170, and     -   K is a constant representative of efficiency, unit conversions         and other factors.

In FIG. 6A the yoke 160 of pump 100 is shown as having been moved to an angular position of angle A=+30° in a first direction relative to the drive axis 102 of pump 100. In this position of yoke 160, pump 100 moves fluid in a first direction at a volume proportional to the rate of rotation of at its drive shaft 170 and cylinder block 130, and the sine of the angle A, which is a relatively high rate of fluid flow as indicated by the relatively long length of the outline arrows representing fluid flow produced by pump 100. Fluid flow is in a first direction that might be described as being “upward” as shown in FIG. 6A.

For a conventional inline axial pump, the fluid flow rate (and pump/motor displacement) is also a function of swash plate angle, but in contrast to bent axis geometry is determined by the tangent of the yoke angle rather than the sine thereof. In a newer type of conventional inline axial pump, the maximum practical drive offset angle (swash plate angle) is about 21° and so the maximum pumped volume is limited by tan 21°=0.383 of displacement. In the present arrangement of pump/motor 100, a drive angle of up to about A=30° is achieved and displacement is limited by sin 30°=0.50 of displacement. As a result, the present pump/motor device 100 provides an increase of about 0.500/0.383=1.305 or about 30.5 percent (%) of displacement relative to conventional pumps of the same cylinder and piston displacement. In more traditional conventional pumps wherein the drive offset angle is limited to about 18° the increase in displacement is about 0.500/0.325=1.538 or about a 53.8 percent (%) relative to conventional pumps of the same cylinder and piston displacement, which is quite significant.

Another artifact which favors the fluid flow rate and displacement advantage of the bent axis geometry over the inline axial geometry involves that the term D, the combined total displacement of all of the pistons in the cylinder block. For an inline axial geometry, the term D is a function of the piston circle diameter in the cylinder, whereas for the bent axis geometry, the term D is a function of the circle diameter of the pistons in the yoke sockets, not the circle diameter of the pistons in the cylinder block. For the inline axial pump, which by definition of being “inline”, predicates that the piston circle diameter be equal to the effective yoke socket circle diameter. However, due to the splaying of the pistons in a bent axis geometry, the yoke socket circle diameter, by geometric necessity, is larger than the piston circle diameter in the cylinder block. Due to this splaying of the piston circle versus yoke spindle socket circle, the bent axis pump has an advantage of greater spindle socket circle diameter than piston (cylinder) circle diameter—typically this is a minimum of about 8 percent (%). The flow advantage of having an increased maximum yoke angle is beneficially increased further by the splayed spindle socket circle diameter of the bent axis geometry.

So, for example, in the present pump/motor device 100 which provides a yoke angle advantage that produces a 30.5 percent (%) increase in displacement, the displacement and therefore the fluid flow thereof is further increased by a factor of 1.08 thereby to provide an overall increase of about 41.0 percent (%) more displacement (and therefore more fluid flow output) relative to conventional inline axial pumps of the same piston cylinder circle and piston diameters. A like result and advantage obtains whether device 100 is employed as a motor, or as a pump, or as a device serving as both a pump and a motor, e.g., at different times and/or under different operating conditions. With yoke 160 pivoted to an angle of A=+30° as in FIG. 6A, the volume of fluid flow provided by pump device 100 from inlet to outlet is substantially at the maximum volume, e.g., 100% of its capacity, which is substantially greater than that of conventional inline axial pumps and of conventional bent axis pumps.

In FIG. 6B the yoke 160 of pump 100 is shown as having been moved to an angular position of angle A=+20° in the first direction relative to the drive axis 102 of pump 100. In this position of yoke 160, pump 100 moves fluid in a first direction at a volume proportional to the rate of rotation of at its drive shaft 170 and cylinder block 130, and the sine of the angle A, which is a relatively moderate rate of fluid flow as indicated by the relatively moderate length of the outline arrows representing fluid flow produced by pump 100. Fluid flow is again in the first direction that might be described as being “upward” as shown in FIG. 6B. With yoke 160 pivoted to an angle of A=+20° as in FIG. 6B, the volume of fluid flow provided by pump device 100 from inlet to outlet is about 68.4% of the maximum volume, e.g., the volume as in FIG. 6A.

In FIG. 6C the yoke 160 of pump 100 is shown as having been moved to an angular position of angle A=+10° in the first direction relative to the drive axis 102 of pump 100. In this position of yoke 160, pump 100 moves fluid in a first direction at a volume proportional to the rate of rotation of at its drive shaft 170 and cylinder block 130, and the sine of the angle A, which is a relatively lower rate of fluid flow as indicated by the relatively shorter length of the outline arrows representing fluid flow produced by pump 100. Fluid flow is again in the first direction that might be described as being “upward” as shown in FIG. 6C. With yoke 160 pivoted to an angle of A=+10° as in FIG. 6C, the volume of fluid flow provided by pump device 100 from inlet to outlet is about 34.7% of the maximum volume, e.g., the volume as in FIG. 6A.

In FIG. 6D the yoke 160 of pump 100 is shown as being moved to a neutral angular position of angle A=0° relative to the drive axis 102 of pump 100. In this position of yoke 160, pump 100 does not move fluid because the sine of the angle A=0° is zero, i.e. sin 0°=0, which is no flow of fluid as indicated by the absence of outline arrows representing fluid flow. A yoke 160 that is movable to both positive and negative angle positions may be referred to as being movable or pivotable “over center” (center being about 0°) and a device having a yoke 160 movable “over center” may be referred to as capable of or having“over center operation.” It is further noted that the direction of rotation of pump 100 remains the same, i.e. reversal of the direction in which shaft 170 is rotated is not required, and that change in the position of yoke 160 over positive and negative yoke angles is sufficient to reverse the direction of fluid flow at ports 120.

In FIG. 6E the yoke 160 of pump 100 is shown as having been moved to an angular position of angle A=−0.10° in a second direction opposite to the first direction relative to the drive axis 102 of pump 100, e.g., over center relative to yoke positions shown in FIGS. 6A-6C. In this A=−A° position of yoke 160, pump 100 moves fluid in a second direction opposite to the first direction at a volume proportional to the rate of rotation of at its drive shaft 170 and cylinder block 130, and the sine of the angle A, which is a relatively lower rate of fluid flow as indicated by the relatively shorter length of the outline arrows representing fluid flow produced by pump 100, however, fluid flow is in a second direction opposite to the first direction that might be described as being “downward” as shown in FIG. 6E. With yoke 160 pivoted to an angle of A=−10° as in FIG. 6E, the volume of fluid flow provided by pump device 100 from inlet to outlet is about 34.7% of the maximum volume, e.g., the volume as in FIG. 6A, but flowing in the opposite direction.

In FIG. 6F the yoke 160 of pump 100 is shown as having been moved to an angular position of angle A=−20° in the second direction opposite to the first direction relative to the drive axis 102 of pump 100. In this position of yoke 160, pump 100 moves fluid in the second direction at a volume proportional to the rate of rotation of at its drive shaft 170 and cylinder block 130, and the sine of the angle A, which is a relatively moderate rate of fluid flow as indicated by the relatively moderate length of the outline arrows representing fluid flow produced by pump 100, however, fluid flow is again in the a second direction that might be described as being “downward” as shown in FIG. 6F. With yoke 160 pivoted to an angle of A=−20° as in FIG. 6F, the volume of fluid flow provided by pump device 100 from inlet to outlet is about 68.4% of the maximum volume, e.g., the volume as in FIG. 6A, but flowing in the opposite direction.

In FIG. 6G the yoke 160 of pump 100 is shown as having been moved to an angular position of angle A=−30° in the second direction opposite to the first direction relative to the drive axis 102 of pump 100. In this position of yoke 160, pump 100 moves fluid in the second direction at a volume proportional to the rate of rotation of at its drive shaft 170 and cylinder block 130, and the sine of the angle A, which is a relatively higher rate of fluid flow as indicated by the relatively longer length of the outline arrows representing fluid flow produced by pump 100, however, fluid flow is again in the second direction that might be described as being “downward” as shown in FIG. 6G. With yoke 160 pivoted to an angle of A=−30° as in FIG. 6G, the volume of fluid flow provided by pump device 100 from inlet to outlet is about 100% of the maximum volume, e.g., the same volume as in FIG. 6A, but flowing in the opposite direction.

Thus, device 100 when employed as a pump 100 is capable of moving fluid in either direction merely by changing the angular position to which the yoke 160 is pivoted, e.g., yoke 160 being pivotable over center to both positive and negative angles A relative to the axis 102 of the input drive, without changing the direction or speed of the input drive, which advantageously simplifies the driving mechanism and devices employed with pump 100, thereby likely resulting in simplified controls, lower weight, lower cost and/or higher reliability. Moreover, only the yoke 160 and spindle 150 rotationally mounted thereon need be pivoted, thereby reducing the size and mass of the rotating parts that must be pivotable for varying displacement of pump 100, and thus likely reducing the overall weight and cost of pump 100.

FIG. 7 includes FIGS. 7A-7G which are a series of partially transparent perspective views showing rotating components of the example bent axis variable delivery inline drive axial piston device 100 employed as a motor 100 with the yoke 160 thereof moved to different angular positions A. In FIGS. 7A-7G the arrows at inlet (P) and outlet (R) drawn in outline represent the input fluid drive applied to device 100 employed as a motor 100, e.g., from a hydraulic or other pressurized source of fluid under pressure, and the arrows drawn in outline near shaft 170 represent the direction and rotational rate of the rotational motion produced at the output shaft 170 of the motor 100. In general, the relation between fluid flow and rotational motion of drive shaft 170 resulting in torque output is proportional to the displacement of cylinder block 130, the rate of rotation thereof and the sine of the angle A between the drive axis 102 and the yoke or spindle axis 161 device, as above.

In FIG. 7A the yoke 160 of motor 100 is shown as having been moved to an angular position of angle A=+30° in a first direction relative to the drive axis 102 of motor 100. In this position of yoke 160, motor 100 responds to the movement of fluid under pressure in a first direction at a given volume to produce a proportional rate of rotation at its drive shaft 170 and cylinder block 130, and proportional to the sine of the angle A, which is a relatively high rate of rotation as indicated by the relatively long length of the arrow representing rotation produced by motor 100, e.g., and with substantially 100% of the maximum available torque. Fluid flow is in the first direction as illustrated might be described as producing clockwise rotation as shown in FIG. 7A.

In FIG. 7B the yoke 160 of motor 100 is shown as having been moved to an angular position of angle A=+20° in the first direction relative to the drive axis 102 of motor 100. In this position of yoke 160, motor 100 responds to the movement of fluid under pressure in the first direction at a given volume by producing a proportional rate of rotation of at its drive shaft 170 and cylinder block 130, and proportional to the sine of the angle A, which is a relatively moderate rate of rotation as indicated by the relatively moderate length of the arrow representing rotation produced by motor 100, e.g., and with about 68.4% of the maximum available torque. Rotation is again in the first direction that might be described as being clockwise as shown in FIG. 7B.

In FIG. 7C the yoke 160 of motor 100 is shown as having been moved to an angular position of angle A=+10° in the first direction relative to the drive axis 102 of motor 100. In this position of yoke 160, motor 100 responds to the movement of fluid under pressure in a first direction at a given volume by producing a proportional rate of rotation of at its drive shaft 170 and cylinder block 130, and proportional to the sine of the angle A, which is a relatively lower rate of rotation as indicated by the relatively shorter length of the arrow representing rotation produced by motor 100, e.g., and with about 37.4% of the maximum available torque. Fluid flow drive is again in the same direction that might be described as being “upward” as shown in FIG. 7C and motor rotation is again clockwise.

In FIG. 7D the yoke 160 of motor 100 is shown as being moved to a neutral angular position of angle A=0° relative to the drive axis 102 of motor 100. In this position of yoke 160, motor 100 does not respond to the movement of fluid under pressure because the sine of the angle A=0° is zero, i.e. sin 0°=0, which produces no rotation as indicated by the absence of an arrow representing rotation. A yoke 160 that is movable to both positive and negative angle positions may be referred to as being movable “over center” (center being about) 0° and a device having a yoke 160 movable or pivotable “over center” may be referred to as capable of or having“over center operation.” It is further noted that the direction of fluid flow at ports 120 remains the same, i.e. reversal of the direction of fluid flow at ports 120 is not required, and that change in the position of yoke 160 over positive and negative yoke angles, e.g., over center, is sufficient to reverse the direction of rotation of motor 100.

In FIG. 7E the yoke 160 of motor 100 is shown as having been moved to an angular position of angle A=−10° in a second direction opposite to the first direction relative to the drive axis 102 of motor 100, e.g., over center relative to yoke positions shown in FIGS. 7A-7C. In this position of yoke 160, motor 100 responds to the movement of fluid under pressure in the first direction at a given volume producing a proportional rate of rotation of at its drive shaft 170 and cylinder block 130, and proportional to the sine of the angle A, which is a relatively lower rate of rotation as indicated by the relatively shorter length of the arrow representing rotation produced by motor 100, e.g., and with about 37.4% of the maximum available torque, however, rotation is in a second direction opposite to the first direction that might be described as being counter-clockwise as shown in FIG. 7E.

In FIG. 7F the yoke 160 of motor 100 is shown as having been moved to an angular position of angle A=−20° in the second direction opposite to the first direction relative to the drive axis 102 of motor 100. In this position of yoke 160, motor 100 responds to the movement of fluid under pressure in the first direction at a given volume to produce a proportional rate of rotation of at its drive shaft 170 and cylinder block 130, and proportional to the sine of the angle A, which is a relatively moderate rate of rotation as indicated by the relatively moderate length of the arrow representing rotation produced by motor 100, e.g., and with about 68.4% of the maximum available torque, however, rotation is again in the a second direction that might be described as being counter-clockwise as shown in FIG. 7F.

In FIG. 7G the yoke 160 of motor 100 is shown as having been moved to an angular position of angle A=−30° in the second direction opposite to the first direction relative to the drive axis 102 of motor 100. In this position of yoke 160, motor 100 responds to the movement of fluid under pressure in the first direction at a given volume to produce a proportional rate of rotation of at its drive shaft 170 and cylinder block 130, and proportional to the sine of the angle A, which is a relatively higher rate of rotation as indicated by the relatively longer length of the arrow representing rotation produced by motor 100, e.g., and with substantially 100% of the maximum available torque, however, rotation is again in the second direction that might be described as being counter clockwise as shown in FIG. 7G.

Thus, device 100 when employed as a motor 100 is capable of responding to movement of fluid under pressure in one direction by producing rotation in either direction merely by changing the angular position to which the yoke 160 is pivoted, e.g., yoke 160 being pivotable over center to both positive and negative angles A relative to the axis 102 of the input drive, without changing the direction or flow of the input fluid under pressure, which advantageously simplifies the fluid driving mechanism and devices employed with motor 100, thereby likely resulting in simplified controls, lower weight, lower cost and/or higher reliability. Moreover, only the yoke 160 and spindle 150 rotationally mounted thereon need be pivoted, thereby reducing the size and mass of the rotating parts that must be pivotable for varying displacement of motor 100, and thus likely reducing the overall weight and cost of motor 100.

FIG. 8 includes FIGS. 8A and 8B which are schematic diagrams representing a parallel and a series configured, respectively, vehicle kinetic energy recovery system (KERS) 300, 300P, 300S and/or vehicle hydraulic hybrid drive systems (HHDS) 300, 300P. 300S employing a pump/motor device 100 as described, wherein the device 100 is employed as a pump and as a motor at different times under different operating modes. The placing of devices in condition to operate as a pump or as a motor at different times is controlled by the movement of yoke 160 as is described below.

In both embodiments, an engine 310, e.g., an internal combustion engine (ICE) 310, which is the primary source of power has a drive shaft 312 (e.g., a crankshaft 312) coupled to the shaft 170 of device 100 through which energy is converted by device 100 from rotational motion/torque applied at shaft 170 into energy stored under pressure in high pressure accumulator device 380H, e.g., by pumping fluid from low pressure accumulator 380L, e.g., a reservoir, to high pressure accumulator 380H, e.g., a pressure storage tank. When the energy stored in high pressure accumulator 380H is needed to assist engine 310, fluid flows from high pressure accumulator 380H to low pressure accumulator 380L via device 100, thereby to apply additional torque via shaft 170 to the drive shaft of engine 310.

In the parallel hybrid system 300P of FIG. 8A, engine 310 drives wheels 360 via transmission 320, drive shaft 330, differential 340 and axles 350, as is conventional in a motorized vehicle. At the same time and in parallel, engine 310 may also drives device 100 which operates as a pump 100 to move fluid through fluid lines 370L, 370H from low pressure accumulator (reservoir) 380L to high pressure accumulator 380H where the fluid is stored under high pressure. Further, deceleration of the vehicle develops torque that is coupled via drive shaft 350, differential 340, drive shaft 330 and transmission 320 through engine 310 to drive device 100 as a pump 100 to move fluid through fluid lines 370H, 370L from low pressure accumulator (reservoir) 380L to high pressure accumulator 380H where the fluid is stored under high pressure, thereby to produce braking torque at wheels 360 while storing kinetic energy removed from the vehicle as potential energy by pressurizing fluid to high pressure in high pressure accumulator vessel 380H.

When additional torque is required, e.g., above the torque available from engine 310, fluid flowing through fluid lines 370H, 370L from high pressure accumulator 380H to low pressure accumulator 380L and through device 100 causes device 100 to operate as a motor 100 to produce driving torque that is coupled to wheels 360 via engine 310, transmission 320, drive shaft 330, differential 340 and axles 350, thereby supplementing the torque available from engine 310.

In the series hybrid system 300S of FIG. 8B, engine 310 is not coupled to and does not directly drive wheels 360, and so there is no need for a transmission 320, drive shaft 330, and differential 340 as in a conventional motorized vehicle. Engine 310 via its drive shaft 312 drives device 100 which operates as a pump 100 to move fluid from low pressure accumulator (reservoir) 380L to high pressure accumulator 380H where the fluid is stored under high pressure, and is available as energy to power the vehicle. In effect wheel drive devices 100W operate similarly to a hydraulic or hydrostatic type of transmission.

To accelerate the vehicle, the accelerating torque required is produced by fluid flowing through fluid lines 370H, 370L from high pressure accumulator 380H to low pressure accumulator 380L and through wheel coupled devices 100W which operate as motors 100W to produce driving torque that is coupled directly from the drive shafts 170 of devices 100W via axles 350 to wheels 360.

To decelerate the vehicle, the decelerating torque required is produced by wheel coupled devices 100W operating as pumps 100W to pump fluid to flow through fluid lines 370H, 370L to high pressure accumulator 380H from low pressure accumulator 380L where the fluid is stored under high pressure, thereby to produce braking torque at wheels 360 while storing kinetic energy removed from the vehicle as potential energy by pressurizing fluid to high pressure in high pressure accumulator vessel 380H.

FIG. 9 includes FIGS. 9A-9H which are a series of partially transparent perspective views showing rotating and movable components of the example bent axis variable delivery inline drive axial piston device 100 employed as a pump and motor 100 in a kinetic energy recovery systems and/or in a hydraulic hybrid drive system with the yoke 160 thereof moved to different angular positions. In FIGS. 9A-9H the arrows drawn in outline represent the input fluid flow to and from device 100 employed as a pump and motor 100, e.g., between a reservoir (R) and a hydraulic or other pressurized source (P) of fluid under pressure, and the arrows drawn in outline represent the direction, torque and/or rotational rate of the rotational motion produced at the shaft 170 of the device 100, e.g., which may be connected to, e.g., a mechanical shaft or transmission or wheel, for utilization in a kinetic energy recovery and/or an hydraulic hybrid drive. In general, the relation between fluid flow and rotational motion of drive shaft 170 is proportional to the displacement of cylinder block 130, the rate of rotation thereof and the sine of the angle A between the drive axis 102 and the yoke or spindle axis 161 device, as above.

The kinetic energy of a moving object, e.g., a truck, bus, car, train, streetcar or other vehicle, must be reduced to slow and/or stop the object and is typically dissipated as heat using friction braking (e.g., common drum or disk brakes) or dynamic braking (e.g., driving an electrical generator connected to resistors). In a kinetic energy recovery system, so as not to waste the kinetic energy that is removed, the kinetic energy is typically converted to another form and is stored in a storage device, e.g., as electrical energy that charges a battery or a capacitor or as rotational kinetic energy stored in a rotating flywheel, from which the stored energy can later be withdrawn and put to use. In a vehicle, the stored energy is often employed to drive the vehicle, as in hybrid gasoline-electric automobiles, trucks and buses.

Because the present arrangement of device 100 allows it to be employed as a pump 100 or as a motor 100 or as both a pump and a motor 100 without reconfiguring its fluid (e.g., hydraulic) and mechanical connections, device 100 is suitable for use in a kinetic energy recovery system and for use in a kinetic energy recovery system (KERS), or in a hydraulic drive (HD) or in another fluid drive system, and/or in a hydraulic hybrid drive (HHD) or other fluid hybrid drive system. In a typical KERS, HD and/or HHD system ports 120 of device 100 are fluidically coupled to a pressurizable fluid container (P) and to a fluid reservoir (R) for moving fluid therebetween, so that by moving fluid to the pressurized container (P) the device 100 and container (P) serve as a storage accumulator wherein kinetic energy is converted and stored as pressurized fluid in the pressurizable container (P) wherein fluid may be stored under pressure, and from which fluid may be withdrawn to utilize the energy stored therein as pressurized fluid.

FIG. 9A illustrates a KERS system in a brakes OFF and throttle OFF condition wherein pump/motor device 100 is in a zero displacement condition, e.g., essentially in “neutral,” with yoke 160 in the center or 0° or zero displacement position wherein axis 161 of yoke 160 is aligned with axis 102 of the drive shaft and so rotation, if any, of the drive shaft 170 does not produce any fluid flow (NO FLOW) at ports 120, and pump/motor 100 provides no resistance and no assistance torque T to the rotation ω of the shaft 170. Thus, if the vehicle is at rest it tends to remain at rest and, if moving, it tends to continue moving, e.g., to coast. The symbolic storage accumulator at the left of FIG. 9A reflects this condition having only a plain line at the bottom thereof indicating a connection without any pressure or fluid flow.

FIG. 9B illustrates a KERS system in a relatively mild brakes ON and throttle OFF condition wherein pump/motor device 100 is operating as a pump 100 with yoke 160 in a position −10° off the center position wherein axis 161 of yoke 160 is angled by about −10° with respect to axis 102 of the drive shaft and so rotation of the drive shaft produces fluid flow at ports 120 pumping fluid from the reservoir (R) to the pressurizable container (P) at outlet port 120, thereby producing a torque T_(B) at the drive shaft 170 which is in a direction opposing the rotation ω thereby to produce a braking action. The relative magnitude of the torque produced is indicated by the relative length of the torque arrow, e.g., a relatively low level of brake application producing a relatively small displacement of device 100 and a relatively low level of braking torque T_(B). Thus, if the vehicle is moving, it tends to be slowed relatively gently by the relatively low torque T_(B) resulting from the small displacement pumping action of device 100. The symbolic storage accumulator has a relatively shorter inward directed arrow at the bottom thereof indicating a relatively low level of pumping that increases the pressure in the pressurized container (P) due to fluid flow produced by device 100, thereby to store energy. The stored pressure is indicated by an inward directed arrow within the accumulator symbol.

FIG. 9C illustrates a KERS system in a relatively moderate brakes ON and throttle OFF condition wherein pump/motor device 100 is operating as a pump 100 with yoke 160 in a position −20° off the center position wherein axis 161 of yoke 160 is angled by about −20° with respect to axis 102 of the drive shaft and so rotation ω of the drive shaft produces fluid flow at ports 120 pumping fluid from the reservoir (R) to the pressurizable container (P) at outlet port 120, thereby producing a torque T_(B) at the drive shaft 170 which is in a direction opposing the rotation ω thereby to produce a braking action. The relative magnitude of the torque T_(B) produced is indicated by the relative length of the torque arrow, e.g., a relatively moderate level of brake application producing a relatively intermediate displacement of device 100 and a relatively intermediate level of braking torque. Thus, if the vehicle is moving, it tends to be slowed relatively moderately by the relatively intermediate torque resulting from the intermediate displacement pumping action of device 100 and by the braking torque T_(B) resulting from the pumping action of device 100. The symbolic storage accumulator has a relatively intermediate length inward directed arrow at the bottom thereof indicating a relatively intermediate level of pumping that increases the pressure in the pressurized container (P) due to fluid flow produced by device 100, thereby storing energy. The stored pressure is indicated by an inward directed arrow within the accumulator symbol.

FIG. 9D illustrates a KERS system in a relatively heavier brakes ON and throttle OFF condition wherein pump/motor device 100 is operating as a pump 100 with yoke 160 in a position −30° off the center position wherein axis 161 of yoke 160 is angled by about −30° with respect to axis 102 of the drive shaft 170 and so rotation of the drive shaft produces fluid flow at ports 120 pumping fluid from the reservoir (R) to the pressurizable container (P) at outlet port 120, thereby producing a torque T_(B) at the drive shaft 170 which is in a direction opposing the rotation ω thereby to produce a braking action. The relative magnitude of the torque T_(B) produced is indicated by the relative length of the torque arrow, e.g., a relatively high level of brake application producing a relatively high displacement of device 100 and a relatively high level of braking torque T_(B). Thus, if the vehicle is moving, it tends to be slowed relatively more quickly by the relatively high torque T_(B) resulting from the higher displacement pumping action of device 100. The symbolic storage accumulator has a relatively longer inward directed arrow at the bottom thereof indicating a relatively higher level of pumping that increases the pressure in the pressurized container (P) due to fluid flow produced by device 100, thereby storing energy. The stored pressure is indicated by an inward directed arrow within the accumulator symbol.

FIG. 9E illustrates a KERS system in a brakes OFF, throttle OFF and KERS not commanded condition as where the system, e.g., may be transitioning from a regeneration mode, e.g., pumping to recover kinetic energy by pumping fluid into the storage container (accumulator) under pressure, to a boost or driving mode, e.g., wherein energy stored in a pressurized container (P) from energy recovered in braking operation is utilized to provide driving torque. In this condition pump/motor device 100 is in a zero displacement condition, e.g., essentially in “neutral,” with yoke 160 is illustrated in the center or 0° or zero displacement position wherein axis 161 of yoke 160 is aligned with axis 102 of the drive shaft and so rotation to, if any, of the drive shaft 170 does not produce any fluid flow (NO FLOW) at ports 120, and pump/motor 100 provides no resistance and no assistance to the rotation of the shaft 170. Thus, if the vehicle is at rest it tends to remain at rest and, if moving, it tends to continue moving, e.g., to coast. The symbolic storage accumulator at the left of FIG. 9A reflects this condition having only a plain line at the bottom thereof indicating a connection without any pressure or fluid flow.

FIG. 9F illustrates a KERS system in a brakes OFF, relatively mild throttle ON and KERS commanded condition wherein pump/motor device 100 is operating as a motor 100 to move energy from the accumulator to a load. In this condition, yoke 160 is illustrated in a position +10° off the center position wherein axis 161 of yoke 160 is angled by about 10° with respect to axis 102 of the drive shaft and so fluid flow at ports 120 produced by pressurized fluid flowing from the pressurized container (P) to reservoir (R) to produce torque T_(D) produces rotation ω of the drive shaft 170, whereby the torque T_(D) produced at the drive shaft 170 is in a direction to increase the rotation ω of drive shaft 170 thereby to produce a driving or accelerating action. The relative magnitude of the torque produced is indicated by the relative lengths of the flow and torque arrows, e.g., a relatively low level of throttle application producing a relatively small displacement of device 100 and a relatively low level of driving torque. Thus, if the vehicle is moving, it tends to be accelerated relatively gently by the relatively low driving torque T_(D) resulting from the small displacement motor action of device 100. The symbolic storage accumulator has a relatively shorter outward directed arrow at the bottom thereof indicating a relatively low level of outflow that reduces the pressure in the pressurized container (P) to produce fluid flow through device 100, thereby to recover energy previously stored. The reducing stored pressure (discharging) of the accumulator is indicated by an outward directed arrow within the accumulator symbol.

FIG. 9G illustrates a KERS system in a brakes OFF, intermediate throttle ON and KERS commanded condition wherein pump/motor device 100 is operating as a motor 100 to move energy from the accumulator to a load. In this condition, yoke 160 is illustrated in a position 20° off the center position wherein axis 161 of yoke 160 is angled by about 20° with respect to axis 102 of the drive shaft and so fluid flow at ports 120 produced by pressurized fluid flowing from the pressurized container (P) to reservoir (R) to produce torque produces rotation w of the drive shaft 170, whereby the torque T_(D) produced at the drive shaft 170 is in a direction to increase the rotation ω of drive shaft 170 thereby to produce an accelerating action. The relative magnitude of the torque T_(D) produced is indicated by the relative lengths of the flow and torque arrows, e.g., a relatively intermediate level of throttle application producing an intermediate displacement of device 100 and an intermediate level of driving torque. Thus, if the vehicle is moving, it tends to be accelerated relatively moderately by the relatively intermediate level of driving torque T_(D) resulting from the intermediate displacement motor action of device 100. The symbolic storage accumulator has a relatively intermediate length outward directed arrow at the bottom thereof indicating an intermediate level of outflow that reduces the pressure in the pressurized container (P) to produce fluid flow through device 100, thereby to recover energy previously stored. The reducing stored pressure (discharging) of the accumulator is indicated by an outward directed arrow within the accumulator symbol.

FIG. 9H illustrates a KERS system in a brakes OFF, relatively high throttle ON and KERS commanded condition wherein pump/motor device 100 is operating as a motor 100 to move energy from the accumulator to a load. In this condition, yoke 160 is illustrated in a position 30° off the center position wherein axis 161 of yoke 160 is angled by about 30° with respect to axis 102 of the drive shaft and so fluid flow at ports 120 produced by pressurized fluid flowing from the pressurized container (P) to reservoir (R) to produce torque T_(D) produces rotation ω of the drive shaft 170, whereby the torque T_(D) produced at the drive shaft 170 is in a direction to increase the rotation ω of drive shaft 170 thereby tending to produce an accelerating action. The relative magnitude of the driving torque T_(D) produced is indicated by the relative lengths of the flow and torque arrows, e.g., a relatively high level of throttle application producing a relatively high displacement of device 100 and a relatively high level of driving torque. Thus, if the vehicle is moving, it tends to be accelerated relatively strongly by the relatively high level of driving torque T_(D) resulting from the relatively high displacement motor action of device 100. The symbolic storage accumulator has a relatively long outward directed arrow at the bottom thereof indicating a relatively high level of outflow that reduces the pressure in the pressurized container (P) to produce fluid flow through device 100, thereby to recover energy previously stored. The reducing stored pressure (discharging) of the accumulator is indicated by an outward directed arrow within the accumulator symbol.

In a typical embodiment, a variable displacement device 100 having a maximum displacement of about 0.5 cubic inch per revolution (about 8.2 cc/rev.) may be about 4 inches (about 10.2 cm) in diameter and about 6 inches (about 15.2 cm) in length, and weighs about 4.5 pounds (about 2.05 Kg). When utilized as a pump 100, rotating shaft 170 at about 6500 rpm can produce a head pressure of about 5000 psi (about 351.5 Kg/cm²) with no flow or a pumping volume of about 14 gallons per minute (about 53 liters per minute) at a pressure of about 4800 psi (about 337.4 Kg/cm²). When utilized as a motor 100, an input fluid pressure at port 120 of about 5000 psi (about 351.5 Kg/cm²) produces a torque of about 33 foot-pounds (about 4.57 Kg-m) at shaft 170, and a fluid flow through ports 120 of about 14 gallons per minute (about 53 liters per minute) causes shaft 170 to rotate at about 6500 rpm.

Typically, housings 180, 190 may be of aluminum, aircraft-grade aluminum, titanium, steel, stainless steel, carbon-fiber reinforced composite, or other suitable material, port plate 110 and ports 120 may be of steel, hardened steel, stainless steel, coated titanium, carbon-graphite (CAGR), silicon carbide (SiC), or other suitable material, cylinder block 130 may be of bronze, ductile iron, aluminum, or other suitable metal, e.g., preferably a soft metal, pistons 142 and connecting rods 140 may be of high strength steel or stainless steel having a wear coating, titanium having a wear coating, or other suitable metal and wear coating, spindle 150 may be of high strength bearing steel or stainless steel, titanium or other suitable metal, yoke 160 may be of high strength steel or stainless steel, titanium, aluminum, or other suitable metal, drive shaft 170 and universal link 200 may be of high strength steel or stainless steel having a wear coating, titanium having a wear coating, or other suitable metal and wear coating. Examples of wear coatings include high-velocity oxygenated flame spray, chrome plating, and the like.

As a result, devices 100 according to the present arrangement can typically have lower weight than and comparable volume to conventional axial inline pumps and motors of similar capacity, while having similar high efficiency (e.g., volumetric, torque and volume efficiency) and higher displacement of a bent axis axial pump, and can be employed as either or both of a pump and a motor, where both can operate over-center variable displacement. When utilized as a pump, a device 100 typically will be more economical, have less power extraction and produce less heat, as well as being smooth running, typically due to the relatively high incidence of rolling interfaces and low incidence of sliding interfaces, relatively little pre-compression and decompression. When utilized as a motor, a device 100 typically will produce more torque with lower pressure and lower fluid flow, and will tend to be smooth running with little stick-slip friction.

When device 100 is utilized in place of a conventional electro-hydraulic actuator (EHA) pump, device 100 is expected to provide at least about 8-10 times higher frequency response, e.g., about an order of magnitude improvement, due to the over-center reversing feature provided by spindle 150 rotatable on yoke 160 as compared to the typical conventional fixed displacement bent-axis EHA pumps for which the direction of rotation of the drive must be reversed to reverse operation of the pump. It is noted that a conventional inline axial pump cannot be utilized as an EHA pump because it is unable to run in opposite directions and is unable to be effectively operated over center.

Moreover, the power required to reverse drive to a conventional EHA pump is not only much higher than, e.g., about twice, that required to move the yoke 160 of device 100 over center, but increases as a faster response is needed, and so device 100 can not only be smaller and lighter, but can also reduce the requirements for the drive motor, for electrical power, for wiring and the like. In addition the fixed direction operation possible with device 100 has substantially less wear, because it can operate at smaller yoke angles than does a fixed displacement device, and is operable with simpler control algorithms than is a conventional EHA pump with reversing drive, because the drive motor 175 is operated in one direction at a constant speed.

In an aircraft or other power transfer unit (PTU) application, device 100 also can replace a conventional fixed displacement bent axis pump where pumping volume and direction are varied by varying the speed of the drive, e.g., an electric motor, the conventional pump producing essentially the same disadvantages as above for an EHA pump. Device 100 can provide similar advantages, e.g., lower drive power, faster response, smaller volume and lighter weight, and simpler controls, as when it replaces a conventional EHA pump in a PTU.

A bent axis, variable displacement inline drive device 100 may comprise: a port plate 110 having a seat for receiving a rotatable cylinder block 130 therein, and having at least two fluid passages each coupled to a respective fluid port 120 and each having an arcuate opening corresponding to a different less than 180° portion of a circle; a cylinder block 130 rotatably mounted adjacent the seat of the port plate 110 for rotation about an axis, the cylinder block 130 having a circular array of axial cylinders 132 therein each having an opening at a seat end thereof adjacent the seat of the port plate 110 and located to be in alternating fluid communication with the respective openings of the two fluid passages at different rotational positions in the rotation of the cylinder block 130; a rotatable shaft 170 coupled through an opening in the port plate 110 to the cylinder block 130 for rotating therewith; a plurality of pistons 142 disposed in the cylinders 132 of the cylinder block 130 for reciprocating motion therein, each the piston having a connecting rod 140 extending from an end of the cylinder block 130 opposite the port plate 110; a rotatable spindle 150 having a circular array of receptacles therein for receiving the respective ends of the connecting rods 140; a pivotable yoke 160 having the spindle 150 rotatably mounted thereon for rotation about an axis, wherein the spindle 150 and plurality of pistons 142 disposed in the cylinder block 130 are connected by the connecting rods 140 for rotating together, the yoke 160 being pivotable for angling the rotational axis of the spindle 150 relative to the rotational axis of the cylinder block 130. The opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132, whereby operating pressure urges the cylinder block 130 toward the port plate 120; or a spring 169 may urge the cylinder block 130 toward the port plate 120; or the opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132 and a spring 169 may urge the cylinder block 132 toward the port plate. The device 100 may further comprise a hold down plate 152 attached to the rotatable spindle 150 and rotatable therewith, wherein the hold down plate 152 retains the ends of the connecting rods 140 in the respective receptacles of the rotatable spindle 150. Each connecting rod 140 may include: a spherical ball 144, 146 at least at one end thereof disposed in a socket of the piston; or a spherical ball 144, 146 at least at the other end thereof disposed in the receptacle of the rotatable spindle 150; or a spherical ball 144, 146 at one end thereof disposed in a socket of the piston and a spherical ball 144, 146 at the other end thereof disposed in the receptacle of the rotatable spindle 150. The device 100 may further comprise a universal link 200 connected at one end to at least one of the shaft 170 and the cylinder block 130 and at an other end to the rotatable spindle 150. The universal link 200 may include: a split spherical ball 204, 206 at least at the one end thereof disposed in a socket at the one of the shaft 170 and the cylinder block 130; or a split spherical ball 204, 206 at least at the other end thereof disposed in a socket at the rotatable spindle 150; or a split spherical ball 204, 206 at each end thereof disposed in respective sockets at the one of the shaft 170 and the cylinder block 130 and at the rotatable spindle 150. The rotatable spindle 150 may include: a movable socket 151 for receiving an end 206 of a universal link 200, wherein the movable socket 151 is movable axially relative to the rotatable spindle 150; and a spring 169 may bias the movable socket 151 towards the universal link 200, whereby the movable socket 151 moves with an effective geometric length of the universal link 200 that changes as the pivotable yoke 160 is pivoted. The yoke 160 may include a base for rotatably supporting the rotatable spindle 150 and a pair of bearing plates 164 extending from the base, wherein the yoke 160 is pivotably supported by a pair of bearings connected to the bearing plates 164 of the yoke 160. The yoke 160 may be pivotable by torque applied at the bearing plate 164 thereof. The spindle 150 may be rotatably supported on the yoke 160 by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing. The device 100 may further comprise: a shaft housing 180 fixedly supporting the port plate 110 and rotatably supporting the shaft 170 and the cylinder block 130. The shaft housing 180 may further comprise: a shaft bearing for rotatably supporting the shaft 170; or a shaft seal surrounding the shaft 170; or a bearing for rotatably supporting the cylinder block 130; or a shaft bearing for rotatably supporting the shaft 170 and a shaft seal surrounding the shaft 170; or a shaft bearing for rotatably supporting the shaft 170 and a bearing for rotatably supporting the cylinder block 130; or a bearing for rotatably supporting the cylinder block 130, a shaft bearing for supporting the shaft 170 and a shaft seal surrounding the shaft 170. The device 100 may further comprise: a yoke 160 housing mounted to the shaft housing 180 for enclosing the yoke 160, the spindle 150 and the connecting rods 140. The device 100 wherein: a power source rotates the shaft 170 to rotate the cylinder block 130 and the spindle 150 thereby to operate the device 100 as a pump pumping fluid through the port plate 110; or fluid flows under pressure to the port plate 110 to rotate the spindle 150 and the cylinder block 130 to operate the device 100 as a motor producing torque and/or rotation at the shaft 170; or a power source rotates the shaft 170 to rotate the cylinder block 130 and the spindle 150 thereby to operate the device 100 as a pump pumping fluid through the port plate 110 and wherein fluid flows under pressure to the port plate 110 to rotate the spindle 150 and the cylinder block 130 to operate the device 100 as a motor producing torque and/or rotation at the shaft 170. The yoke 160 may be pivotable over center relative to the rotational axis of the cylinder block 130 for reversing the direction of fluid flow between the respective fluid ports 120 when the device 100 is utilized as a pump and for reversing the direction of rotation of the shaft 170 when the device 100 is utilized as a motor.

A bent axis, variable displacement inline drive pump device 100 may comprise: a port plate 110 having a seat for receiving a rotatable cylinder block 130 therein, and having at least two fluid passages each coupled to a respective fluid port 120 and each having an arcuate opening corresponding to a different less than 180° portion of a circle; a cylinder block 130 rotatably mounted adjacent the seat of the port plate 110 for rotation about an axis, the cylinder block 130 having a circular array of axial cylinders 132 therein each having an opening at a seat end thereof adjacent the seat of the port plate 110 and located to be in alternating fluid communication with the respective openings of the two fluid passages at different rotational positions in the rotation of the cylinder block 130; a rotatable shaft 170 coupled through an opening in the port plate 110 to the cylinder block 130 for rotating therewith; a plurality of pistons 142 disposed in the cylinders 132 of the cylinder block 130 for reciprocating motion therein, each the piston having a connecting rod 140 extending from an end of the cylinder block 130 opposite the port plate 110; a rotatable spindle 150 having a circular array of receptacles therein for receiving the respective ends of the connecting rods 140; a pivotable yoke 160 having the spindle 150 rotatably mounted thereon for rotation about an axis, wherein the spindle 150 and plurality of pistons 142 disposed in the cylinder block 130 are connected by the connecting rods 140 for rotating together, the yoke 160 being pivotable for angling the rotational axis of the spindle 150 relative to the rotational axis of the cylinder block 130. The opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132, whereby operating pressure urges the cylinder block 130 toward the port plate 120; or a spring 169 may urge the cylinder block 130 toward the port plate 120; or the opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132 and a spring 169 may urge the cylinder block 132 toward the port plate. The device 100 may further comprise a hold down plate 152 attached to the rotatable spindle 150 and rotatable therewith, wherein the hold down plate 152 retains the ends of the connecting rods 140 in the respective receptacles of the rotatable spindle 150. Each connecting rod 140 may include: a spherical ball 144, 146 at least at one end thereof disposed in a socket of the piston; or a spherical ball 144, 146 at least at the other end thereof disposed in the receptacle of the rotatable spindle 150; or a spherical ball 144, 146 at one end thereof disposed in a socket of the piston and a spherical ball 144, 146 at the other end thereof disposed in the receptacle of the rotatable spindle 150. The device 100 may further comprise a universal link 200 connected at one end to at least one of the shaft 170 and the cylinder block 130 and at an other end to the rotatable spindle 150. The universal link 200 may include: a split spherical ball 204, 206 at least at the one end thereof disposed in a socket at the one of the shaft 170 and the cylinder block 130; or a split spherical ball 204, 206 at least at the other end thereof disposed in a socket at the rotatable spindle 150; or a split spherical ball 204, 206 at each end thereof disposed in respective sockets at the one of the shaft 170 and the cylinder block 130 and at the rotatable spindle 150. The rotatable spindle 150 may include: a movable socket 151 for receiving an end 206 of a universal link 200, wherein the movable socket 151 is movable axially relative to the rotatable spindle 150; and a spring 169 may bias the movable socket 151 towards the universal link 200, whereby the movable socket 151 moves with an effective geometric length of the universal link 200 that changes as the pivotable yoke 160 is pivoted. The yoke 160 may include a base for rotatably supporting the rotatable spindle 150 and a pair of bearing plates 164 extending from the base, wherein the yoke 160 is pivotably supported by a pair of bearings connected to the bearing plates 164 of the yoke 160. The yoke 160 may be pivotable by torque applied at the bearing plate 164 thereof. The spindle 150 may be rotatably supported on the yoke 160 by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing. The device 100 of claim 1 may further comprise: a shaft housing 180 fixedly supporting the port plate 110 and rotatably supporting the shaft 170 and the cylinder block 130. The shaft housing 180 may further comprise: a shaft bearing for rotatably supporting the shaft 170; or a shaft seal surrounding the shaft 170; or a bearing for rotatably supporting the cylinder block 130; or a shaft bearing for rotatably supporting the shaft 170 and a shaft seal surrounding the shaft 170; or a shaft bearing for rotatably supporting the shaft 170 and a bearing for rotatably supporting the cylinder block 130; or a bearing for rotatably supporting the cylinder block 130, a shaft bearing for supporting the shaft 170 and a shaft seal surrounding the shaft 170. The device 100 may further comprise: a yoke 160 housing mounted to the shaft housing 180 for enclosing the yoke 160, the spindle 150 and the connecting rods 140. The device 100 wherein: a power source rotates the shaft 170 to rotate the cylinder block 130 and the spindle 150 thereby to operate the pump device 100 for pumping fluid through the port plate 110. The yoke 160 may be pivotable over center relative to the rotational axis of the cylinder block 130 for reversing the direction of fluid flow between the respective fluid ports 120 of the pump device 100.

A bent axis, variable displacement inline drive device 100 may comprise: a port plate 110 having a seat for receiving a rotatable cylinder block 130 therein, and having at least two fluid passages each coupled to a respective fluid port 120 and each having an arcuate opening corresponding to a different less than 180° portion of a circle; a cylinder block 130 rotatably mounted adjacent the seat of the port plate 110 for rotation about an axis, the cylinder block 130 having a circular array of axial cylinders 132 therein each having an opening at a seat end thereof adjacent the seat of the port plate 110 and located to be in alternating fluid communication with the respective openings of the two fluid passages at different rotational positions in the rotation of the cylinder block 130; a rotatable shaft 170 coupled through an opening in the port plate 110 to the cylinder block 130 for rotating therewith; a plurality of pistons 142 disposed in the cylinders 132 of the cylinder block 130 for reciprocating motion therein, each the piston having a connecting rod 140 extending from an end of the cylinder block 130 opposite the port plate 110; a rotatable spindle 150 having a circular array of receptacles therein for receiving the respective ends of the connecting rods 140; a pivotable yoke 160 having the spindle 150 rotatably mounted thereon for rotation about an axis, wherein the spindle 150 and plurality of pistons 142 disposed in the cylinder block 130 are connected by the connecting rods 140 for rotating together, the yoke 160 being pivotable for angling the rotational axis of the spindle 150 relative to the rotational axis of the cylinder block 130. The opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132, whereby operating pressure urges the cylinder block 130 toward the port plate 120; or a spring 169 may urge the cylinder block 130 toward the port plate 120; or the opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132 and a spring 169 may urge the cylinder block 132 toward the port plate. The device 100 may further comprise a hold down plate 152 attached to the rotatable spindle 150 and rotatable therewith, wherein the hold down plate 152 retains the ends of the connecting rods 140 in the respective receptacles of the rotatable spindle 150. Each connecting rod 140 may include: a spherical ball 144, 146 at least at one end thereof disposed in a socket of the piston; or a spherical ball 144, 146 at least at the other end thereof disposed in the receptacle of the rotatable spindle 150; or a spherical ball 144, 146 at one end thereof disposed in a socket of the piston and a spherical ball 144, 146 at the other end thereof disposed in the receptacle of the rotatable spindle 150. The device 100 may further comprise a universal link 200 connected at one end to at least one of the shaft 170 and the cylinder block 130 and at an other end to the rotatable spindle 150. The universal link 200 may include: a split spherical ball 204, 206 at least at the one end thereof disposed in a socket at the one of the shaft 170 and the cylinder block 130; or a split spherical ball 204, 206 at least at the other end thereof disposed in a socket at the rotatable spindle 150; or a split spherical ball 204, 206 at each end thereof disposed in respective sockets at the one of the shaft 170 and the cylinder block 130 and at the rotatable spindle 150. The rotatable spindle 150 may include: a movable socket 151 for receiving an end 206 of a universal link 200, wherein the movable socket 151 is movable axially relative to the rotatable spindle 150; and a spring 169 may bias the movable socket 151 towards the universal link 200, whereby the movable socket 151 moves with an effective geometric length of the universal link 200 that changes as the pivotable yoke 160 is pivoted. The yoke 160 may include a base for rotatably supporting the rotatable spindle 150 and a pair of bearing plates 164 extending from the base, wherein the yoke 160 is pivotably supported by a pair of bearings connected to the bearing plates 164 of the yoke 160. The yoke 160 may be pivotable by torque applied at the bearing plate 164 thereof. The spindle 150 may be rotatably supported on the yoke 160 by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing. The device 100 of claim 1 may further comprise: a shaft housing 180 fixedly supporting the port plate 110 and rotatably supporting the shaft 170 and the cylinder block 130. The shaft housing 180 may further comprise: a shaft bearing for rotatably supporting the shaft 170; or a shaft seal surrounding the shaft 170; or a bearing for rotatably supporting the cylinder block 130; or a shaft bearing for rotatably supporting the shaft 170 and a shaft seal surrounding the shaft 170; or a shaft bearing for rotatably supporting the shaft 170 and a bearing for rotatably supporting the cylinder block 130; or a bearing for rotatably supporting the cylinder block 130, a shaft bearing for supporting the shaft 170 and a shaft seal surrounding the shaft 170. The device 100 of claim 9 may further comprise: a yoke 160 housing mounted to the shaft housing 180 for enclosing the yoke 160, the spindle 150 and the connecting rods 140. The device 100 wherein: fluid flows under pressure to the port plate 110 to rotate the spindle 150 and the cylinder block 130 to operate the device 100 as a motor producing torque and/or rotation at the shaft 170. The yoke 160 may be pivotable over center relative to the rotational axis of the cylinder block 130 for reversing the direction of rotation of the shaft 170 of the motor device 100.

A bent axis, variable displacement inline drive device rotating group 130-160 may comprise: a cylinder block 130 rotatably mountable for rotation about an axis, the cylinder block 130 having a circular array of axial cylinders 132 therein each having an opening at a seat end of the cylinder block 130 located to be in alternating fluid communication with respective openings of two fluid passage openings of a port plate 110 at different rotational positions in the rotation of the cylinder block 130 when a port plate 110 is adjacent the cylinder block 130; the cylinder block 130 having a central opening at the seat end thereof for receiving a rotatable shaft 170, whereby a rotatable shaft 170 may be coupled to the cylinder block 130 through an opening in a port plate 110 for rotating therewith; a plurality of pistons 142 disposed in the cylinders 132 of the cylinder block 130 for reciprocating motion therein, each the piston having a connecting rod 140 extending from an end of the cylinder block 130 opposite the seat end thereof; a rotatable spindle 150 having a circular array of receptacles therein for receiving the respective ends of the connecting rods 140; a pivotable yoke 160 having the spindle 150 rotatably mounted thereon for rotation about an axis, wherein the spindle 150 and the plurality of pistons 142 disposed in the cylinder block 130 are connected by the connecting rods 140 for rotating together, the yoke 160 being pivotable for angling the rotational axis of the spindle 150 relative to the rotational axis of the cylinder block 130. The opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132, whereby operating pressure urges the cylinder block 130 toward the port plate 120; or a spring 169 may urge the cylinder block 130 toward the port plate 120; or the opening 133 at the seat end of each axial cylinder 132 may have a smaller diameter than does the axial cylinder 132 and a spring 169 may urge the cylinder block 132 toward the port plate. The rotating group 130-160 may further comprise a hold down plate 152 attached to the rotatable spindle 150 and rotatable therewith, wherein the hold down plate 152 retains the ends of the connecting rods 140 in the respective receptacles of the rotatable spindle 150. Each connecting rod 140 may include: a spherical ball 144, 146 at least at one end thereof disposed in a socket of the piston; or a spherical ball 144, 146 at least at the other end thereof disposed in the receptacle of the rotatable spindle 150; or a spherical ball 144, 146 at one end thereof disposed in a socket of the piston and a spherical ball 144, 146 at the other end thereof disposed in the receptacle of the rotatable spindle 150. The rotating group 130-160 may further comprise a universal link 200 connected at one end to at least one of the shaft 170 and the cylinder block 130 and at an other end to the rotatable spindle 150. The universal link 200 may include: a split spherical ball 204, 206 at least at the one end thereof disposed in a socket at the one of the shaft 170 and the cylinder block 130; or a split spherical ball 204, 206 at least at the other end thereof disposed in a socket at the rotatable spindle 150; or a split spherical ball 204, 206 at each end thereof disposed in respective sockets at the one of the shaft 170 and the cylinder block 130 and at the rotatable spindle 150. The rotatable spindle 150 may include: a movable socket 151 for receiving an end 206 of a universal link 200, wherein the movable socket 151 is movable axially relative to the rotatable spindle 150; and a spring 169 may bias the movable socket 151 towards the universal link 200, whereby the movable socket 151 moves with an effective geometric length of the universal link 200 that changes as the pivotable yoke 160 is pivoted. The yoke 160 may include a base for rotatably supporting the rotatable spindle 150 and a pair of bearing plates 164 extending from the base, wherein the yoke 160 may be pivotably supported by a pair of bearings connected to the bearing plates 164 of the yoke 160. The yoke 160 may be pivotable by torque applied at the bearing plate 164 thereof. The spindle 150 may be rotatably supported on the yoke 160 by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing. The rotating group 130-160 may further comprise: a housing rotatably supporting the cylinder block 130 and a bearing in the housing for rotatably supporting the cylinder block 130. The yoke 160 may be pivotable over center relative to the rotational axis of the cylinder block 130 for reversing the direction of fluid flow between the respective fluid passages of a port plate 120 when the device rotating group 130-160 is utilized in a pump and for reversing the direction of rotation of the cylinder block 130 when the device rotating group 130-160 is utilized in a motor.

As used herein, the term “about” means that dimensions, sizes, formulations, parameters, shapes and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In general, a dimension, size, formulation, parameter, shape or other quantity or characteristic is “about” or “approximate” whether or not expressly stated to be such. It is noted that embodiments of very different sizes, shapes and dimensions may employ the described arrangements.

Although terms such as “up,” “down,” “left,” “right,” “front,” “rear,” “side,” “top,” “bottom,” “forward,” “backward,” “under” and/or “over,” and the like may be used herein as a convenience in describing one or more embodiments and/or uses of the present arrangement, the articles described may be positioned in any desired orientation and/or may be utilized in any desired position and/or orientation. Such terms of position and/or orientation should be understood as being for convenience only, and not as limiting of the invention as claimed.

Further, what is stated as being “optimum” or “deemed optimum” may or may not be a true optimum condition, but is the condition deemed to be desirable or acceptably “optimum” by virtue of its being selected in accordance with the decision rules and/or criteria defined by the designer and/or applicable controlling function, e.g., an optimum operating condition of pressure, fluid flow and shaft rotation may be specified even though the device 100 may typically be operated at a different operating condition or over a range of operating conditions, and the optimum condition may be different when device 100 is utilized as a pump than when it is utilized as a motor.

While the present invention has been described in terms of the foregoing example embodiments, variations within the scope and spirit of the present invention as defined by the claims following will be apparent to those skilled in the art. For example, connecting rods 140 are illustrated as having an example ball and socket connection to pistons 142 and at spindle 150, however, such connection need not be provided at pistons 142 and other arrangements, e.g., shoes or sliders, could be provided at spindle 150.

Further, cylinder block 130 and shaft 170 may be two separate pieces connected by one or more splines or keys as illustrated, or may be a single piece, either machined or permanently fixed together.

Still further, pistons 142 may be one piece and assembled to connecting rods 140, e.g., by swaging the lip of socket 143 of piston 142 to capture and retain the ball end 144 of rod 140 therein, or may be two pieces, the piston and an annular plug, that are assembled with the annular plug being pressed into socket 143 to capture and retain ball end 144 of rod 140 to piston 142. In addition and/or alternatively, connecting rods 140 may be a single piece as illustrated, or may be two pieces each comprising a ball end 144, 146 and a portion of the smaller diameter connecting shaft that connects balled ends 144, 146. The portions of the connecting shaft are joined together, e.g., by welding, either before or after balled end 144 is captured and retained in socket 143 of piston 142, e.g., by welding of the connecting shaft.

Typically, hold down plate 152 that captures and retains balled ends 146 of connecting rods 140 in the sockets 153 of spindle 150 may have circular openings through which piston connecting rods 140 pass and each circular opening may have a radial slot that connects the circular opening and the perimeter of hold down plate 152 so that the connecting shaft part of connecting rod 140 may pass through the radial slots. Alternatively, where connecting rods 140 are provided in two pieces, one piece thereof could be passed through the circular opening of hold down plate 152 before the two portions of the connecting shaft of connecting rod 140 are welded together.

In KERS and/or HD systems, either two or four-wheel drive may be provided, by conventional transmissions and drive shafts in a parallel hybrid system and by plural wheel drive devices 100W in a series hybrid system. In a parallel two wheel drive hybrid system, the two wheels not mechanically driven may be driven by wheel drive devices 100W thereby to provide a pseudo series/parallel arrangement wherein all four wheels may be driven, two by mechanical coupling from engine 310 and the other two by fluid drive devices 100W.

Each of the U.S. Provisional Applications, U.S. patent applications, and/or U.S. patents identified herein are hereby incorporated herein by reference in their entirety, for any purpose and for all purposes irrespective of how it may be referred to herein.

Finally, numerical values stated are typical or example values, are not limiting values, and do not preclude substantially larger and/or substantially smaller values. Values in any given embodiment may be substantially larger and/or may be substantially smaller than the example or typical values stated. 

What is claimed is:
 1. A bent axis, variable displacement inline drive device comprising: a port plate having a seat for receiving a rotatable cylinder block therein, and having at least two fluid passages each coupled to a respective fluid port and each having an arcuate opening corresponding to a different less than 180° portion of a circle; a cylinder block rotatably mounted adjacent the seat of said port plate for rotation about an axis, said cylinder block having a circular array of axial cylinders therein each having an opening at a seat end thereof adjacent the seat of said port plate and located to be in alternating fluid communication with the respective openings of the two fluid passages at different rotational positions in the rotation of said cylinder block; a rotatable shaft coupled through an opening in said port plate to said cylinder block for rotating therewith; a plurality of pistons disposed in the cylinders of said cylinder block for reciprocating motion therein, each said piston having a connecting rod extending from an end of said cylinder block opposite the port plate; a rotatable spindle having a circular array of receptacles therein for receiving the respective ends of said connecting rods; a pivotable yoke having said spindle rotatably mounted thereon for rotation about an axis, wherein said spindle and plurality of pistons disposed in said cylinder block are connected by said connecting rods for rotating together, said yoke being pivotable for angling the rotational axis of said spindle relative to the rotational axis of said cylinder block, whereby said pivotable yoke is pivotable over center.
 2. The device of claim 1 wherein: the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder, whereby operating pressure urges said cylinder block toward said port plate; or a spring urges said cylinder block toward said port plate; or the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder and a spring urges said cylinder block toward said port plate.
 3. The device of claim 1 further comprising a hold down plate attached to said rotatable spindle and rotatable therewith, wherein said hold down plate retains the ends of said connecting rods in the respective receptacles of said rotatable spindle.
 4. The device of claim 1 wherein each said connecting rod includes: a spherical ball at least at one end thereof disposed in a socket of said piston; or a spherical ball at least at the other end thereof disposed in the receptacle of said rotatable spindle; or a spherical ball at one end thereof disposed in a socket of said piston and a spherical ball at the other end thereof disposed in the receptacle of said rotatable spindle.
 5. The device of claim 1 further comprising a universal link connected at one end to at least one of said shaft and said cylinder block and at an other end to said rotatable spindle.
 6. The device of claim 5 wherein said universal link includes: a split spherical ball at least at the one end thereof disposed in a socket at the one of said shaft and said cylinder block; or a split spherical ball at least at the other end thereof disposed in a socket at said rotatable spindle; or a split spherical ball at each end thereof disposed in respective sockets at the one of said shaft and said cylinder block and at said rotatable spindle.
 7. The device of claim 1 wherein said rotatable spindle includes: a movable socket for receiving an end of a universal link, wherein said movable socket is movable axially relative to said rotatable spindle; and a spring biasing said movable socket towards said universal link, whereby the movable socket moves with an effective geometric length of said universal link that changes as said pivotable yoke is pivoted.
 8. The device of claim 1 wherein said yoke includes a base for rotatably supporting said rotatable spindle and a pair of bearing plates extending from said base, wherein said yoke is pivotably supported by a pair of bearings connected to the bearing plates of said yoke.
 9. The device of claim 8 wherein said yoke is pivotable by torque applied at the bearing plate thereof.
 10. The device of claim 1 wherein said spindle is rotatably supported on said yoke by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing.
 11. The device of claim 1 further comprising: a shaft housing fixedly supporting said port plate and rotatably supporting said shaft and said cylinder block.
 12. The device of claim 11 wherein said shaft housing further comprises: a shaft bearing for rotatably supporting said shaft; or a shaft seal surrounding said shaft; or a bearing for rotatably supporting said cylinder block; or a shaft bearing for rotatably supporting said shaft and a shaft seal surrounding said shaft; or a shaft bearing for rotatably supporting said shaft and a bearing for rotatably supporting said cylinder block; or a bearing for rotatably supporting said cylinder block, a shaft bearing for supporting said shaft and a shaft seal surrounding said shaft.
 13. The device of claim 11 further comprising: a yoke housing mounted to said shaft housing for enclosing said yoke, said spindle and said connecting rods.
 14. The device of claim 1 wherein: a power source rotates said shaft to rotate said cylinder block and said spindle thereby to operate said device as a pump pumping fluid through said port plate; or fluid flows under pressure to said port plate to rotate said spindle and said cylinder block to operate said device as a motor producing torque and/or rotation at said shaft; or a power source rotates said shaft to rotate said cylinder block and said spindle thereby to operate said device as a pump pumping fluid through said port plate and wherein fluid flows under pressure to said port plate to rotate said spindle and said cylinder block to operate said device as a motor producing torque and/or rotation at said shaft.
 15. The device of claim 1 wherein said yoke is pivotable over center relative to the rotational axis of said cylinder block for reversing the direction of fluid flow between the respective fluid ports when said device is utilized as a pump and for reversing the direction of rotation of said shaft when said device is utilized as a motor.
 16. A bent axis, variable displacement inline drive pump device comprising: a port plate having a seat for receiving a rotatable cylinder block therein, and having at least two fluid passages each coupled to a respective fluid port and each having an arcuate opening corresponding to a different less than 180° portion of a circle; a cylinder block rotatably mounted adjacent the seat of said port plate for rotation about an axis, said cylinder block having a circular array of axial cylinders therein each having an opening at a seat end thereof adjacent the seat of said port plate and located to be in alternating fluid communication with the respective openings of the two fluid passages at different rotational positions in the rotation of said cylinder block; a rotatable shaft coupled through an opening in said port plate to said cylinder block for rotating therewith; a plurality of pistons disposed in the cylinders of said cylinder block for reciprocating motion therein, each said piston having a connecting rod extending from an end of said cylinder block opposite the port plate; a rotatable spindle having a circular array of receptacles therein for receiving the respective ends of said connecting rods; a pivotable yoke having said spindle rotatably mounted thereon for rotation about an axis, wherein said spindle and plurality of pistons disposed in said cylinder block are connected by said connecting rods for rotating together, said yoke being pivotable for angling the rotational axis of said spindle relative to the rotational axis of said cylinder block, whereby said pivotable yoke is pivotable over center.
 17. The device of claim 16 wherein: the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder, whereby operating pressure urges said cylinder block toward said port plate; or a spring urges said cylinder block toward said port plate; or the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder and a spring urges said cylinder block toward said port plate.
 18. The device of claim 16 further comprising a hold down plate attached to said rotatable spindle and rotatable therewith, wherein said hold down plate retains the ends of said connecting rods in the respective receptacles of said rotatable spindle.
 19. The device of claim 16 wherein each said connecting rod includes: a spherical ball at least at one end thereof disposed in a socket of said piston; or a spherical ball at least at the other end thereof disposed in the receptacle of said rotatable spindle; or a spherical ball at one end thereof disposed in a socket of said piston and a spherical ball at the other end thereof disposed in the receptacle of said rotatable spindle.
 20. The device of claim 16 further comprising a universal link connected at one end to at least one of said shaft and said cylinder block and at an other end to said rotatable spindle.
 21. The device of claim 20 wherein said universal link includes: a split spherical ball at least at the one end thereof disposed in a socket at the one of said shaft and said cylinder block; or a split spherical ball at least at the other end thereof disposed in a socket at said rotatable spindle; or a split spherical ball at each end thereof disposed in respective sockets at the one of said shaft and said cylinder block and at said rotatable spindle.
 22. The device of claim 16 wherein said rotatable spindle includes: a movable socket for receiving an end of a universal link, wherein said movable socket is movable axially relative to said rotatable spindle; and a spring biasing said movable socket towards said universal link, whereby the movable socket moves with an effective geometric length of said universal link that changes as said pivotable yoke is pivoted.
 23. The device of claim 16 wherein said yoke includes a base for rotatably supporting said rotatable spindle and a pair of bearing plates extending from said base, wherein said yoke is pivotably supported by a pair of bearings connected to the bearing plates of said yoke.
 24. The device of claim 23 wherein said yoke is pivotable by torque applied at the bearing plate thereof.
 25. The device of claim 16 wherein said spindle is rotatably supported on said yoke by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing.
 26. The device of claim 16 further comprising: a shaft housing fixedly supporting said port plate and rotatably supporting said shaft and said cylinder block.
 27. The device of claim 26 wherein said shaft housing further comprises: a shaft bearing for rotatably supporting said shaft; or a shaft seal surrounding said shaft; or a bearing for rotatably supporting said cylinder block; or a shaft bearing for rotatably supporting said shaft and a shaft seal surrounding said shaft; or a shaft bearing for rotatably supporting said shaft and a bearing for rotatably supporting said cylinder block; or a bearing for rotatably supporting said cylinder block, a shaft bearing for supporting said shaft and a shaft seal surrounding said shaft.
 28. The device of claim 26 further comprising: a yoke housing mounted to said shaft housing for enclosing said yoke, said spindle and said connecting rods.
 29. The device of claim 16 wherein: a power source rotates said shaft to rotate said cylinder block and said spindle thereby to operate said pump device for pumping fluid through said port plate.
 30. The device of claim 16 wherein said yoke is pivotable over center relative to the rotational axis of said cylinder block for reversing the direction of fluid flow between the respective fluid ports of said pump device.
 31. A bent axis, variable displacement inline drive motor device comprising: a port plate having a seat for receiving a rotatable cylinder block therein, and having at least two fluid passages each coupled to a respective fluid port and each having an arcuate opening corresponding to a different less than 180° portion of a circle; a cylinder block rotatably mounted adjacent the seat of said port plate for rotation about an axis, said cylinder block having a circular array of axial cylinders therein each having an opening at a seat end thereof adjacent the seat of said port plate and located to be in alternating fluid communication with the respective openings of the two fluid passages at different rotational positions in the rotation of said cylinder block; a rotatable shaft coupled through an opening in said port plate to said cylinder block for rotating therewith; a plurality of pistons disposed in the cylinders of said cylinder block for reciprocating motion therein, each said piston having a connecting rod extending from an end of said cylinder block opposite the port plate; a rotatable spindle having a circular array of receptacles therein for receiving the respective ends of said connecting rods; a pivotable yoke having said spindle rotatably mounted thereon for rotation about an axis, wherein said spindle and plurality of pistons disposed in said cylinder block are connected by said connecting rods for rotating together, said yoke being pivotable for angling the rotational axis of said spindle relative to the rotational axis of said cylinder block, whereby said pivotable yoke is pivotable over center.
 32. The device of claim 31 wherein: the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder, whereby operating pressure urges said cylinder block toward said port plate; or a spring urges said cylinder block toward said port plate; or the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder and a spring urges said cylinder block toward said port plate.
 33. The device of claim 31 further comprising a hold down plate attached to said rotatable spindle and rotatable therewith, wherein said hold down plate retains the ends of said connecting rods in the respective receptacles of said rotatable spindle.
 34. The device of claim 31 wherein each said connecting rod includes: a spherical ball at least at one end thereof disposed in a socket of said piston; or a spherical ball at least at the other end thereof disposed in the receptacle of said rotatable spindle; or a spherical ball at one end thereof disposed in a socket of said piston and a spherical ball at the other end thereof disposed in the receptacle of said rotatable spindle.
 35. The device of claim 31 further comprising a universal link connected at one end to at least one of said shaft and said cylinder block and at an other end to said rotatable spindle.
 36. The device of claim 35 wherein said universal link includes: a split spherical ball at least at the one end thereof disposed in a socket at the one of said shaft and said cylinder block; or a split spherical ball at least at the other end thereof disposed in a socket at said rotatable spindle; or a split spherical ball at each end thereof disposed in respective sockets at the one of said shaft and said cylinder block and at said rotatable spindle.
 37. The device of claim 31 wherein said rotatable spindle includes: a movable socket for receiving an end of a universal link, wherein said movable socket is movable axially relative to said rotatable spindle; and a spring biasing said movable socket towards said universal link, whereby the movable socket moves with an effective geometric length of said universal link that changes as said pivotable yoke is pivoted.
 38. The device of claim 31 wherein said yoke includes a base for rotatably supporting said rotatable spindle and a pair of bearing plates extending from said base, wherein said yoke is pivotably supported by a pair of bearings connected to the bearing plates of said yoke.
 39. The device of claim 38 wherein said yoke is pivotable by torque applied at the bearing plate thereof.
 40. The device of claim 31 wherein said spindle is rotatably supported on said yoke by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing.
 41. The device of claim 31 further comprising: a shaft housing fixedly supporting said port plate and rotatably supporting said shaft and said cylinder block.
 42. The device of claim 41 wherein said shaft housing further comprises: a shaft bearing for rotatably supporting said shaft; or a shaft seal surrounding said shaft; or a bearing for rotatably supporting said cylinder block; or a shaft bearing for rotatably supporting said shaft and a shaft seal surrounding said shaft; or a shaft bearing for rotatably supporting said shaft and a bearing for rotatably supporting said cylinder block; or a bearing for rotatably supporting said cylinder block, a shaft bearing for supporting said shaft and a shaft seal surrounding said shaft.
 43. The device of claim 41 further comprising: a yoke housing mounted to said shaft housing for enclosing said yoke, said spindle and said connecting rods.
 44. The device of claim 31 wherein: fluid flows under pressure to said port plate to rotate said spindle and said cylinder block to operate said device as a motor producing torque and/or rotation at said shaft.
 45. The device of claim 31 wherein said yoke is pivotable over center relative to the rotational axis of said cylinder block for reversing the direction of rotation of the shaft of said motor device.
 46. A bent axis, variable displacement inline drive device rotating group comprising: a cylinder block rotatably mountable for rotation about an axis, said cylinder block having a circular array of axial cylinders therein each having an opening at a seat end of said cylinder block located to be in alternating fluid communication with respective openings of plural fluid passages of a port plate at different rotational positions in the rotation of said cylinder block when a port plate is adjacent said cylinder block; said cylinder block having a central opening at the seat end thereof for receiving a rotatable shaft, whereby a rotatable shaft may be coupled to said cylinder block through an opening in a port plate for rotating therewith; a plurality of pistons disposed in the cylinders of said cylinder block for reciprocating motion therein, each said piston having a connecting rod extending from an end of said cylinder block opposite the seat end thereof; a rotatable spindle having a circular array of receptacles therein for receiving the respective ends of said connecting rods; a pivotable yoke having said spindle rotatably mounted thereon for rotation about an axis, wherein said spindle and said plurality of pistons disposed in said cylinder block are connected by said connecting rods for rotating together, said yoke being pivotable for angling the rotational axis of said spindle relative to the rotational axis of said cylinder block, whereby said pivotable yoke is pivotable over center.
 47. The device rotating group of claim 46 wherein: the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder, whereby operating pressure urges said cylinder block toward said port plate; or a spring urges said cylinder block toward said port plate; or the opening at the seat end of each axial cylinder has a smaller diameter than does said axial cylinder and a spring urges said cylinder block toward said port plate.
 48. The device rotating group of claim 46 further comprising a hold down plate attached to said rotatable spindle and rotatable therewith, wherein said hold down plate retains the ends of said connecting rods in the respective receptacles of said rotatable spindle.
 49. The device rotating group of claim 46 wherein each said connecting rod includes: a spherical ball at least at one end thereof disposed in a socket of said piston; or a spherical ball at least at the other end thereof disposed in the receptacle of said rotatable spindle; or a spherical ball at one end thereof disposed in a socket of said piston and a spherical ball at the other end thereof disposed in the receptacle of said rotatable spindle.
 50. The device rotating group of claim 46 further comprising a universal link connected at one end to at least one of said shaft and said cylinder block and at an other end to said rotatable spindle.
 51. The device rotating group of claim 50 wherein said universal link includes: a split spherical ball at least at the one end thereof disposed in a socket at the one of said shaft and said cylinder block; or a split spherical ball at least at the other end thereof disposed in a socket at said rotatable spindle; or a split spherical ball at each end thereof disposed in respective sockets at the one of said shaft and said cylinder block and at said rotatable spindle.
 52. The device rotating group of claim 46 wherein said rotatable spindle includes: a movable socket for receiving an end of a universal link, wherein said movable socket is movable axially relative to said rotatable spindle; and a spring biasing said movable socket towards said universal link, whereby the movable socket moves with an effective geometric length of said universal link that changes as said pivotable yoke is pivoted.
 53. The device rotating group of claim 46 wherein said yoke includes a base for rotatably supporting said rotatable spindle and a pair of bearing plates extending from said base, wherein said yoke is pivotably supported by a pair of bearings connected to the bearing plates of said yoke.
 54. The device rotating group of claim 53 wherein said yoke is pivotable by torque applied at the bearing plate thereof.
 55. The device rotating group of claim 46 wherein said spindle is rotatably supported on said yoke by an axial bearing; or by a radial bearing; or by an axial bearing and a radial bearing.
 56. The device rotating group of claim 46 further comprising: a housing rotatably supporting said cylinder block and a bearing in said housing for rotatably supporting said cylinder block.
 57. The device rotating group of claim 46 wherein said yoke is pivotable over center relative to the rotational axis of said cylinder block for reversing the direction of fluid flow between the respective fluid passages of a port plate when said device rotating group is utilized in a pump and for reversing the direction of rotation of said cylinder block when said device rotating group is utilized in a motor. 